Download the Hirens BootCD 10 4 Torrent or choose other Hirens BootCD 10 4 torrent. Hirens BootCD 10 4[H33T][NexTG] 188 MB: 0: 0 Hirens BootCD 9 4 incl.

For your security we will auto-log you out, whithin the next 5 minutes, unless you click continue my session. A lot of methods are available to recover or reset the Windows password. The famous is used for recovering the password. Even i have posted about using. But the problem is that its bulky in size. We need to download a file of size 500MB to recover the password.

So I thought why to recover a lost password, instead why cant we simply reset or delete the password using a 3 MB file open source program. That is what this post is about. I have not found any other method simpler than this one, it resets your password in the blink of an eye. The method uses an open source program called.

We can use a USB Disk Drive (Pen Drive) or burn a bootable CD for this method. Follow the Steps below: Step 1: Download the cd080802.zip file from the link below and extract it. It contains an ISO file. Size: 3.15 MB (Updated Working Link 13-01-10) Step 2: Burn the ISO file to a CD. If you are using a USB drive, then mount the cd080802.iso file to a virtual drive. Open the Virtual Drive and Copy all the contents to your USB disk.

If any error comes while copying just skip the file. Now to make the USB Drive Bootable open a Command Prompt(Press Start + R, Type cmd and enter) and type the following commands: Sl.

Command: Action: 1 j: Enter 2 syslinux.exe –ma j: Enter Here j is my drive letter, you should enter your own drive letter. Step 3: Now start the System which you want to reset the password by putting the CD or the USB in the Computer. While start up you have to make sure that it boots up from the correct device i.e.

From the CD or the USB. In order to do this go to your BIOS settings and change the boot order as CD or the USB drive as the first option. Or if you know the Boot menu key then press it and Boot from the correct device. Note: Step 4 to Step 8 takes a very less amount of time.

No need to worry! Step 4: After booting from the CD or the USB, press enter to continue the boot process. In the first step it will automatically select the disk where your windows is installed. Simply press enter to continue. In the Second Step it Will select the path and registry files. Select 1 for password reset (It will select 1 by default, just enter). Step 5: Now after selecting the paths, It will ask “What to do?” Simply press enter as it will automatically select 1 for Edit User Password.

Step 6: It will show a list your system usernames and their password status. Now enter the username whose password you want to reset.

It is case sensitive so, be careful and type what you see in the users list. (If the user is Administrator just press enter as it has already selected Administrator by default otherwise enter the correct username) Step 7: It will show you User Edit Menu. Select 1 to clear the user password. Step 8: It will clear the password. Now Enter “!” to quit from the User select menu.

It will again ask “What to do?”. Enter “q” to quit. Now in step four it will ask you to write the files or not. Enter “y” to write the files.

It will write the files back. Now Simply press enter when it asks for “New run?” as it has selected no by default. The password reset has been successfully completed. Press the power button. Now start the computer and you will find that it is not asking for password for the user you had selected. That’s it, you are done.

This method will remove your password not recover. If you do not want to reset the password, you can recover it. Visit: for password recovery. The method has been tested for windows XP, Windows Vista and Windows 7 and all resulted in success.

This is for information purposes only. We are not responsible for any damages or illegal acts resulting from this information. The information provided here should be used for legal purposes only. USB Disk method will not work if your motherboard or BIOS does not support USB booting. Featured Post: Hiren’s BootCD (also known as Hiren BootCD, Hirens Boot Disk, Hiren Boot Disk or HBCD) is a bootable software ISO containing a large number of Freeware diagnostic programs In the past it also contained several commercially available software programs, but since version 11 it almost entirely contains Freeware. For Comprehensive list of programs see Although the normal method of running Hirens Boot Disk is to burn Hiren’s.BootCD.15.1.iso to a CD and then boot from the CD, an easier and more versatile method is to burn the Hirens Boot CD ISO to a USB Flash Drive.

This has to be one of the most useful things I have come across recently – it gives you a portable fast-loading stripped down copy of Windows XP that boots fast from a USB flash drive. You can boot a dead or malfunctioning system, copy data – such as valuable images and files – back to the USB flash drive. It can also be used to recover the drivers from a dead system, and passwords – such as Windows XP or Windows 7 product key, Office product key etc. Hirens Boot Instructions & Getting Started Tutorial: Step 1: Download Hiren’s Boot Disk Hirens Boot CD Download: See Contents of the Hirens Download Zip File (500 MB): Step 2 download YUMI – Multiboot USB Creator Download: This is an easy way of making a Bootalble USB FlashDrive for Hirens Boot Disk Yumi is run as a stand-alone installer. Insert your USB Flash drive and run Yumi. Your flash drive will be detected. In the Yumi Multiboot Menu, scroll down to Hiren’s Boot CD and browse the location of your downloaded Hiren’s.BootCD.15.1.iso and press Create An 8gb Flash drive leaves considerable space for copying and moving data from an unbootable PC – so we can add a folder called RECOVERED where we can copy data from the PC we are working on.

3: Booting a dead PC with the Bootable Hiren Boot USB Flash Drive • To boot from the Bootable Hiren Boot CD USB Disk, the boot order needs to be changed, so that the computer will t boot from the USB Storage before the hard drive • It is often possible to change the boot order by pressing F12 or F8 just after the system starts to power up – this image shows the Boot Menu that comes up after pressing F12 on a Dell PC. • If the system won’t boot from the Bootable Hiren Bootcd USB Disk – you need to change the boot order in the BIOS • Just after the system starts, press Del or F1 to enter the Bios. The boot order can be set usually from the Advanced Boot Configuration menu. • If the bios is password protected, open the PC and remove the CMOS battery for a moment or so.

This should remove the password protection (and all other bios settings – which will need to be set up again – usually only the Date and Boot order are essential) • Allow the system to boot up from the Bootable Hirens USB Flash Drive This is the boot menu that comes up – select Mini Windows XP and press Enter Mini XP starts to load. Mini XP Loading Hiren’s Boot CD desktop showing the program launcher at bottom RHS The HBCD Menu pops up showing the programs available: The Program Launcher can be undocked from the system tray You can now use Hirens Boot CD to recover your files and copy them back to the USB Flash Drive, or perform other diagnostic operations Refer to on how to burn ISO images to a disc or use or Contents of Hirens Boot CD 15.1 from.

• Avira AntiVir Personal (): Free anti-virus and anti-spyware on-demand scanner, detects and removes more than 50000 viruses and trojans. • ClamWin Free Antivirus 0.97.3 (): A free antivirus, GNU GPL Open Source Virus Scanner. • ComboFix (): Designed to cleanup malware infections and restore settings modified by malware. • Dr.Web CureIt! Antivirus: a free standalone anti-virus and anti-spyware on-demand scanner (downloadable). • GMER 1.0.15: Hidden services, hidden registry, hidden file scanner, Rootkit Detector and Remover.

• Malwarebytes Anti-Malware 1.51.1 (): anti-malware application that can thoroughly remove even the most advanced malware. • Remove Fake Antivirus 1.82: a tool to remove virus/malware which disguises itself to be an antivirus and produces fake alert/warnings and urge you to purchase a useless copy of the fake antivirus. • RootkitRevealer 1.7.1: Rootkit Revealer is an advanced patent-pending root kit detection utility. • Spybot – Search & Destroy 1.6.2 (): Application to scan for spyware, adware, hijackers and other malicious software.

• SuperAntispyware 5.0.1134 (): Remove Adware, Malware, Parasites, Rootkits, Spyware, Trojan, and Worms (a must have tool). • TDSSKiller 2.6.21.0: To remove malware belonging to the family Rootkit.Win32.TDSS aka Tidserv, TDSServ and Alureon.

• CloneDisk 1.9.6: All in one tool for MBR, Partition, Disk, VMWare Disk images vmdk/vmx/vhd, and much more. • COPYR.DMA Build013: A Tool for making copies of hard disks with bad sectors. • CopyWipe 1.14: Copy old hard drive to a new hard drive by copying the entire contents of one drive to another, CopyWipe can also help prevent confidential or private data from being recovered, by securely wiping the contents of a drive. • DiskImage 1.6: Creates and writes disk images files to hard and floppy disks. • DriveImage XML 2.30: backup any drive/partition to an image file, even if the drive is currently in use, a very good freeware alternative to Ghost / Acronis • Drive SnapShot 1.40: creates an exact Disk Image of your system into a file while windows is running. • FastCopy 2.08: The Fastest Copy/Delete Software on Windows. • G4L Ghost 4 Linux 0.34a: a hard disk and partition imaging and cloning tool similar to Norton Ghost.

• GImageX 2.0.17: ImageX is used to backup/restore WIM images for Windows XP/Vista and Windows 7. • Image For Dos 2.66: Q uickly, easily, and reliably create a complete image backup of all the data located on your hard drive, backups made to CD/DVD/BD are bootable. • Image For Windows 2.66: Backup and restore utility that creates a snapshot of a selected partition or volume, and saves it to disk, or burns it directly to most DVD+RW+R-R-RW or CD-R/RW drives. • ImgBurn 2.5.6.0: Lightweight CD/DVD/HD DVD/Blu-ray burning application, supports BIN, CUE, DI, DVD, GI, IMG, ISO, MDS, NRG and PDI, Ability to build DVD/HD/BD Video discs from a VIDEO_TS/HVDVD_TS/BDAV/BDMV folder, Unicode folder/file names (formerly DVD Decrypter). • InfraRecorder 0.52: An Open source CD/DVD burning software, also create/burn.iso images. • Macrium Reflect 4.2.3775: Create complete backups of your disk partitions, including operating system, installed programs and all your settings. • ODIN 0.3.4: Open Disk Imager in a Nutshell is similar to Drive Snapshot which supports backing up windows while you are using it.

• Partition Image – PartImage 0.6.9: supported filesystem includes Ext2, Ext3, Reiserfs, HFS, HPFS, JFS, Xfs, UFS, Fat16, Fat32 and NTFS. • Partition Saving 3.90: A tool to backup/restore partitions (SavePart.exe).

• RegBak 1.0: a light-weight and simple utility to create backups of Windows registry files. • Raw Copy 1.2: Useful tool to transfer the data directly from a faulty drive to another drive, built in data recovery function which will also attempt to recover data from bad sectors. • ShadowCopy 2.00: Copy all your files and entire system – even if they are locked by Windows. • SelfImage 1.2.1.92: to create image files of any mounted or unmounted hard disk partition. • Seagate DiscWizard 11.8326: Backup drive/partition to an image file, for Seagate owners (Powered by Acronis TrueImage) • TeraCopy 2.12: TeraCopy is a compact program designed to copy and move files at the maximum possible speed, providing the user a lot of features includes pause, resume, auto shutdown, verify, error recovery and unicode support.

• WhitSoft File Splitter 4.5a: a Small File Split / Join Tool. • XXClone 0.58.0: The simple way to clone a Windows disk to another disk, it makes a self-bootable clone of Windows system disk. • 7-Zip 9.22: File archiver with a high compression ratio Supports 7z, ARJ, BZIP2, CAB, CHM, CPIO, DEB, DMG, FAT, GZ, GZIP, HFS, IMA, IMG, ISO, LZH, LZMA, MBR, MSI, NSIS, NTFS, RAR, RPM, TAR, UDF, VHD, WIM, XAR, XZ, ZIP and Z formats. • Bulk Rename Utility 2.7.1.2: Rename multiple files, change timestamps and rename using EXIF data with the click of a button. • Dos Command Center 5.1: Classic dos-based file manager. • Dos Navigator 6.4.0: Dos File Manager, Norton Commander clone but has much more features. • EasyUHA 1.1: GUI Tool to create and extract UHA Archives.

• Everything 1.21: Ultra fast file/folder search tool with ftp/http server. • Explore2fs 1.08b: GUI explorer tool for accessing linux ext2 and ext3 filesystems under windows. • Ext2Explore 2.2.71: To explore ext2/ext3/ext4 disk/partition, can also be used to view and copy disk and file system images.

• File Maven 3.5: an advanced Dos file manager with high speed PC-to-PC file transfers via serial or parallel cable. • File Wizard 1.35: a file manager – colored files, drag and drop copy, move, delete etc. • FastLynx 2.0: Dos file manager with Pc to Pc file transfer capability.

• HashMyFiles 1.72: Calculate MD5/SHA1/CRC32 hashes of your files. • Mini Windows Xp: Portable Windows Xp that runs from CD/USB/Ram Drive to repair/recover dead windows operating system. It has LAN and WLAN (Wireless) Network includes 300 WiFi/Ethernet card drivers and can also be customized easily to add your own drivers in HBCD Drivers folder. Added some USB 3.0 and SATA/SCSI/SAS Storage drivers, Dynamic disk Spanned/Striped/Mirrored/RAID-5 Volume support, PDF Printer and VBS/WSH scripting support. Supported keyboard layouts are: United States, United Kingdom, US Dvorak, Arabic, Turkish Q, Turkish F, Swiss German, Swiss French, Swedish, Suomi Finnish, Spanish, Slovenian, Slovak, Russian, Portuguese, Polish, Norvegian Norske, Netherlands Dutch, Latin American, Italy, Icelandic, Hungarian, Hebrew, Germany, German Switzerland Luxembourg, Francais Cavier AZERTY, Denmark Daenish, Bulgarian Phonetic, Bulgarian, Brazil Portuguese, Brazil Extended Portuguese and Belgium.

• Opera Web Browser 11.01: One of the fastest, smallest and smartest full-featured web browser with an email client. • SearchMyFiles 1.80: Alternative to ‘Search For Files And Folders’ module of Windows + Duplicates Search. • Total Commander 7.56a: A file manager similar to the Windows Explorer features side-by-side file-browsing panes, built-in FTP, archive management, file search/compare/synchronize and more. • Volkov Commander 4.99: Dos File Manager with LongFileName/ntfs support (Similar to Norton Commander). • WinMerge 2.12.4.0: Differencing and merging tool which can compare both folders and files, presenting differences in a visual text format that is easy to understand and handle. • All Users Temp Cleaner 1.1: To clean all users temp folders, unwanted windows files from an offline installation. • ATF Cleaner 3.0.0.2: A personal and easy-to-use temp file removal software to clean all user temp folders, Java cache, Opera/Mozilla browser cache, cookies, history, download history, saved passwords etc.

• CCleaner 3.12.1572: Crap Cleaner is a freeware system optimization and privacy tool. 4.5.2: Removes junk files from all user profiles that accumulate over time and litter your hard drive. • CloneSpy 2.62: Duplicate file cleanup tool, can optionaly create hardlinks to save space. • Data Shredder 1.0: A tool to Erase disk and files (also wipe free space) securely. • Delete Doctor 2.2: Delete Files that are hard to delete, Option to delete on reboot or via UNC Name. • Duplicate File Finder 3.5: Scans and identify duplicate files, it compares them based on byte for byte comparison ensures 100% accuracy. • MyUninstaller 1.74: Alternative to the standard add / remove control panel module.

• PC Decrapifier 2.2.8: Removes unwanted preinstalled/bundled software from Windows XP/Vista/7 that usually comes with HP/Dell/Acer etc machines. • Print Flush 1.3: To clean the print spool it restarts the print spooler and deletes junk print files. • Revo Uninstaller 1.93: Remove unnecessary files and registry entries left behind by incomplete program uninstallation routines. • SpaceMonger 1.4: keeping track of the free space on your computer. • SpaceSniffer 1.1.2.0: Find lost space on your disks the easy way. • WinDirStat 1.1.2.80: a disk usage statistics viewer and cleanup tool for Windows. • 3DP Chip 11.10: This tool will help you to find right drivers for your devices and download the latest device drivers with few simple clicks.

• Device Doctor 2.0: Scans the hardware and checks to see if there are new driver updates available, also checks for the unidentified devices. • Double Driver 4.1: Driver Backup and Restore tool. • PCI 32 Sniffer 1.4 (): device information tool which is similar to unknown devices. • Smart Driver Backup 2.12: Easy backup of your Windows device drivers (also works from PE). • UnknownDevices 1.4.20 (): helps you find what those unknown devices in Device Manager really are.

• USBDeview 1.95: View/Uninstall all installed/connected USB devices on your system. • Atlantis Word Processor 1.6.5.5: Compact, fast-loading, but still powerful and efficient, perfect companion for a wide range of your word processing tasks, supports RTF, MS Word DOC 6.0//XP/2003 and DOCX. • HxD 1.7.7.0: Hex Editor provides tools to inspect and edit files, main memory, disks/disk images. • IrfanView 4.30: A free Image Viewer/Editor/Converter and Optimizer.

• Notepad++ 5.9.3: A text editor and source code editor supports Unicode files, Regular expression find and replace (also in files), tabbed editing, Syntax highlighting and Drag-and-drop. • PhotoFiltre 6.5.2: A complete image retouching program (Mini Photoshop) allows you to do simple or advanced adjustments to an image and apply a vast range of filters on it. • Picture Viewer 1.94: Picture viewer for dos, supports more then 40 filetypes. • QuickView Pro 2.58: movie viewer for dos, supports many format including divx. • Spread32 1.18: Mini Excel with all of the basic features of a spreadsheet program. Run macros, draw objects, generate charts, calculate functions and formulas, reads and writes xls, csv, text, and pxl formats. • SumatraPDF 1.1: a free, open source, lightweight PDF Reader for Microsoft Windows.

• AlternateStreamView 1.31: View/Copy/Delete hidden NTFS Alternate Data Streams. • EditBINI 1.0 1: to Edit boot.ini on NTFS Partition. • Ext2fsd 0.51: Linux ext2/ext3 file system driver which supports read and write support in Minixp. • FileDisk Mount Tool 25: to mount ISO/BIN/NRG/MDF/IMA/IMG images on windows. • Filemon 7.04: Monitors and displays file system activity on a system in real-time. • Junction 1.04: Create/View/Delete Windows junction/reparse points on an NTFS drive.

• NewSID 4.10: utility that changes the security ID (SID) for Windows NT, 2000 and XP. • NTFS Access 2.1: Set NTFS permissions recursively and full access rights to a folder/file owner. • NTFS Dos 3.02: to read-only access ntfs partitions from Dos. • NTFS4Dos 1.9: to read and write ntfs partitions from Dos. • NTFSLinksView 1.05: To view list of all symbolic links, junctions and their target paths.

• Virtual Floppy Drive 2.1: enables you to create and mount a virtual floppy drive on your NT/2000/XP/Vista. • Active Kill Disk 4.1.2393: Securely overwrites and destroys all data on physical drive. • CrystalDiskInfo 4.0.1: HDD health monitoring utility, displays basic HDD information, monitors S.M.A.R.T. Values and disk temperature. • Darik’s Boot and Nuke (DBAN) 1.0.7: Completely deletes the contents of any hard disk it can detect.

• DiskView 2.4: to view graphical map of your disk, allowing you to check where a file is located or, by clicking on a cluster, seeing which file occupies it. • DiskWipe 1.2: Securely erases the contents of a disk replacing it with random data or leaving the drive completely blank.

• ExcelStor’s ESTest 4.50: ExcelStor hard disk diagnostic utility. • Fujitsu HDD Diagnostic Tool 7.00: to check IDE drives for possible defects/problems. • Fujitsu IDE Low Level Format 1.0: Low Level Format Tool for Fujitsu Drives. • Gateway GwScan 5.12: Gateway hard drive diagnostic utility. • Hard Disk Sentinel 1.00.5: Hard Disk health, performance and temperature monitoring tool. • HDTune 2.55: HD Tune is a hard disk health, benchmarking, error scanner and information tool.

• HDAT2 4.53: the main function is testing and repair (regenerates) bad sectors for detected devices. A freeware alternative of HDD Regenerator. • HDD Capacity Restore 1.2: This tool allows you to restore factory capacity of any hard drive.

It does not read from or write to the user data area or perform any kind of formatting, only alters HDD firmware (HPA and DCO settings). • HDD Erase 4.0: Secure erase using a special feature built into most newer hard drives. • HDD Low Level Format Tool 2.36: Low-level format tool for S-ATA (SATA), IDE (E-IDE), SCSI, USB, Flash Cards and FIREWIRE external drive enclosures.

• HDD Scan 3.3: HDDScan is a Low-level HDD diagnostic tool, it scans surface find bad sectors etc. • IBM Hitachi Drive Fitness Test 4.16: quickly and reliably tests SCSI, IDE and SATA drives. • IBM Hitachi Feature Tool 2.15: allows you to control some of the features of the the HDD. • Maxtor amset utility 4.0: Utility for changing Acoustic Management on the hard drives. • Maxtor Low Level Formatter 1.1: Maxtor’s Low Level Format Utility works on any harddrive. • Maxtor PowerMax 4.23: designed to perform diagnostic read/write verifications on Maxtor/Quantum hard drives. • MHDD 4.6: Precise diagnostic of the mechanical part of a drive, perform Low-level format, Bad Sector Sepair, access raw sectors, manage S.M.A.R.T.

(SMART) and other drive parameters such as acoustic management, security, Host Protected Area, etc. • Samsung Disk Diagnose (SHDIAG) 1.28: to diagnose the disk when suspected to have failures. • Samsung ESTOOL 3.01 v: Drive Diagnostic, Automatic Acoustic Management, Enable/Disable SMART etc. • Samsung HDD Utility(HUTIL) 2.10: The Drive Diagnostic Utility.

• SeaTools for Dos: GUI 2.23 Text 1.10 versions to test Seagate or Maxtor Parallel ATA (PATA and IDE) and Serial ATA (SATA) interface disc drives. • SmartUDM 2.00: Hard Disk Drive S.M.A.R.T. • Toshiba Hard Disk Diagnostic 2.00b: Toshiba hard drive diagnostic utility. • Victoria 3.33e and 3.52rus: a freeware program for low-level HDD diagnostics.

• Victoria 4.46: Universal program for testing storage devices • ViVard 1.0: HDD low-level diagnostics, Surface test with remap, SMART-attributes etc. • WDClear 1.30: Restore/Erases the drive back to a factory condition. • WDIDLE3 1.05: Modifies the behavior of a Western Digital Green drive to wait longer before positioning the heads in their park position and turning off unnecessary electronics. • Western Digital Data Lifeguard Tools 11.2: for the installation of Western Digital EIDE Hard Drives. • Western Digital Diagnostics (DLGDIAG) 5.19: to quickly and efficiently verify the status of the drive. • Western Digital Data Lifeguard Tools 1.24: to perform drive identification, diagnostics, and repairs on most WD drives. • BellaVista 1.1.0.66: Formerly BCD Editor with lots of options to configure Windows for a developer.

• Boot Partition 2.60: add Partition in the Windows NT/2000/XP Multi-boot loader. • BootFix Utility: Run this utility if you get ‘Invalid system disk’ message. • BootSect 6.0.6: Boot Sector Manipulation Tool, This tool replaces FixFAT.exe and FixNTFS.exe. • BootICE 0.9.2011.0512: a boot sector manipulation utility to edit MBR/PBR/BCD. • DiskMan 4.2: all in one tool for cmos, bios, bootrecord and more. • FbInst 1.6: A tool to create universal flash boot disk that boots from all computers. • Grub4Dos installer 1.1: an universal boot loader GRUB for DOS GRLDR installer.

• grub4dos 2011-12-06: an universal boot loader based on GNU GRUB, can boot off DOS/LINUX or via Windows boot manager/syslinux/lilo or from MBR/CD, builtin BIOS disk emulation. • HDHacker 1.4: Load/Save/View MBR and BootSector from a physical/logical drive. • isolinux 4.04: a boot loader for Linux/i386 that operates off ISO 9660/El Torito CD-ROMs in ‘no emulation’ mode.

• MBRWizard 3.0.73: Directly update and modify the Master Boot Record. • MbrFix 1.3: to backup, restore, fix the boot code in the MBR. • MBR Utility 1.05: to manipulate a drive’s master boot record (MBR) via the command line. • MBRWork 1.08: a utility to perform some common and uncommon MBR functions. • MBRTool 2.3.200: backup, verify, restore, edit, refresh, remove, display, re-write and more. • MBR SAVE / RESTORE 2.1: BootSave and BootRest tools to save / restore MBR.

• MemDisk 4.04: to allow booting legacy operating systems, floppy images, hard disk images and some ISO images. • PLoP Boot Manager 5.0.13: a small program to boot different operating systems harddisk, floppy, CD/DVD or from USB, it can boot from an USB/CD/DVD even without BIOS support. • RMPrepUSB 2.1.620: Partition and format your USB drive and make it bootable. • Smart Boot Manager 3.7.1: a multi boot manager. • XOSL 1.1.5: A graphical boot manager that supports multi-booting of various operating systems. • 1394 Firewire Support: 1394 Firewire Drivers for Dos.

• ASUSTeK USB Driver 3: ASUS USB CD-ROM Device Driver Version 1.00. • Dos tools: Collection of dos utilities 7zdec.exe extract.exe pkzip.exe pkunzip.exe lha.exe gzip.exe uharcd.exe imgExtrc.exe xcopy.exe diskcopy.com mouse.com undelete.com edit.com fdisk.exe fdisk2.exe fdisk3.exe lf.exe delpart.exe wipe.com zap.com format.com deltree.exe more.com find.exe hex.exe debug.exe split.exe mem.exe attrib.com sys.com smartdrv.exe xmsdsk.exe killer.exe share.exe scandisk.exe guest.exe doskey.exe duse.exe move.exe setver.exe intersvr.exe interlnk.exe loadlin.exe lfndos.exe doslfn.com and more. • Interlnk support at COM1/LPT1: to access another computer from COM/LPT port. • SCSI Support: SCSI Drivers for Dos. • SATA Support: SATA Driver (gcdrom.sys) and JMicron JMB361 (xcdrom.sys) for Dos.

• Universal USB Driver 2: Panasonic v2.20 ASPI Manager for USB mass storage. • USB CD-Rom Driver 1: Standard usb_cd.sys driver for cd drive. • Angry IP Scanner 2.21: Scan IP addresses in any range as well as any their ports. • Complete Internet Repair 1.2.8.1283: All in one tool to repair common internet connection issues, it attempts to repair everything internet related on a Windows system.

• CurrPorts 1.96: displays the list of all currently opened TCP and UDP ports on your computer. • Network Password Recovery 1.32: Recover Windows XP/Vista network passwords / Credentials file.

• PuTTY 0.60 r3: PuTTY Tray is a free and open source terminal emulator application which can act as a client for the SSH and Telnet. • SoftPerfect Network Scanner 5.2.3: Multi-threaded IP, NetBIOS and SNMP scanner with a modern interface and many advanced features.

• SmartSniff 1.85: Network monitoring utility that allows you to capture TCP/IP packets that pass through your network adapter. • TCPView 3.05: Lists TCP and UDP endpoints, including the Local/Remote addresses of TCP connections. • TFtpd32 4.0: Tftpd32 is for Trivial File Transfer Protocol (TFTP) client, including DHCP, TFTP, SNTP and Syslog servers, can also be used for PXE boot.

• WinSCP 4.3.5: A free and open source SFTP/FTP client to secure file transfer between a local and a remote computer. • WirelessNetView 1.38: Wireless Net View monitors the activity of wireless networks around you.

• XP TCP/IP Repair 1.0: Repair your Windows XP Winsock and TCP/IP registry errors. • Calcute 11.5.27: A compact scientific tape calculator with many features. • Don’t Sleep 2.42: Temporarily suspend power management and prevent system shutdown, Standby, Hibernate, Turn Off and Restart. • Fix NTLDR is missing: Fix ‘NTLDR is missing, Press any key to restart’ for Windows Xp. • HBCD Customizer 3.0: HBCDCustomizer.exe is a GUI tool to create custom iso images of Hiren’s BootCD.

• HBCD Program Launcher 3.2: Hiren’s BootCD Program launcher (HBCDMenu.exe and HBCDMenu.csv) can be used to launch all these programs from USB/CD. • Mouse Emulator 2.2: You can use your keyboard numpad as a mouse, very useful if your mouse broken or if you are having USB driver problems. • NT 6.x fast installer: Install Windows Vista/7 directly to hard drive/usb extenal drive. • On-Screen Keyboard: A utility that displays a virtual keyboard on the computer screen that allows people with mobility impairments to type data by using a pointing device or joystick. • Parted Magic 6.7: Linux based rescue environment with lots of applications to manage partitions, backup and recovery such as GParted, Parted, Partition Image, TestDisk, Partimage, Truecrypt, Clonezilla, G4L, Firefox, ClamAV, GSmartControl, SimpleBurn, dd, ddrescue, with extensive collection of file system tools are also included, supports the following: btrfs, ext2, ext3, ext4, fat16, fat32, hfs, hfs+, jfs, linux-swap, ntfs, reiserfs, reiser4, and xfs.

• Universal TCP/IP Network 6.5: MSDOS Network Client to connect via TCP/IP to a Microsoft based network. The network can either be a peer-to-peer or a server based network, it contains 98 different network card drivers. • WinNTSetup 1.5.0.3: Install Windows 2k/XP/2003 x86/x64 from USB/CD under PE/LiveXp, allows you to apply tweaks and choose driveletter for the new Windows installation. • eXtended Fdisk 0.9.3: XFDISK allows easy partition creation and edition. • Fat32 Formatter GUI 1.01: Windows XP cannot format a volume bigger than 32GB with FAT32. • GParted Partition Editor 0.9.1: to create, copy, paste, delete, hide, resize or move partitions without losing data, a good freeware alternative to Partition Magic.

• Mount Drives 1.1: Auto Mount Drives can be used to mount unmounted/hidden drives. • Partition Table Editor 8.0: Partition Table and Boot Record Editor. • Partition Wizard Home Edition 7.0: Free Partition Magic Alternative, Partition Resize/Move/Copy/Create/Delete/Format/Convert, Explore, etc. • Ranish Partition Manager 2.44: a boot manager and hard disk partitioner. • Smart Fdisk 2.05: a simple harddisk partition manager. • SPecial Fdisk 2000.03v: SPFDISK is a partition tool.

• Super Fdisk 1.0: Create, delete, format partitions drives without destroying data. • The Partition Resizer 1.3.4: move and resize your partitions in one step. • USB Format Tool: Format/make bootable any USB flash drive to FAT, FAT32, or NTFS partition. • Volume Serial Number Changer 1.2: Allow you to change the drive’s serial number on FAT, FAT32 and NTFS file systems. • ATAPWD 1.2: Hard Disk Password Utility. • Autologon 3.01: Enables you to easily configure Windows’ built-in autologon mechanism, so you don’t have to wait on the login screen.

• BIOS Master Password Generator: Collection of password generator tools to reset BIOS Power on Password / Administrator password on Acer, Compaq, Dell, Fujitsu Siemens, Hewlett Packard, Phoenix, Samsung and other generic brand Laptops. • BulletsPassView 1.10: Reveal the passwords stored behind the bullet (asterisk) characters in Windows / IE (Updated Asterisk Logger). • Content Advisor Password Remover 1.01: It Removes Content Advisor Password from Internet Explorer. • Dialupass 3.16: Find and extract Username, Password, and Domain of DialUp/RAS/VPN networking in Windows. • Kon-Boot 1.0: to bypass Login Password of Windows (32bit, any password) and Linux login as kon-usr. • LicenseCrawler 1.6.0.182: find the license keys and serial numbers of your programs. • Mail PassView 1.77: Recovers mail passwords of Outlook Express, MS Outlook, IncrediMail, Eudora, etc.

• MessenPass 1.42: A password recovery tool that reveals the passwords of several instant messangers. • NTPWD: utility to reset windows nt/2000/xp administrator/user password. • NTPWEdit 0.3: Password editor for Windows NT based systems to change or remove passwords for local system accounts. • Offline NT Password Changer 2011-05-11: utility to reset/unlock windows NT/2000/XP/Vista/7 administrator/user password. • Password Renew 1.1: Utility to set/reset windows NT/2000/XP/Vista/7 (32bit only) passwords. • ProduKey 1.53: Recovers lost the product key of your Windows/Office.

• PST (Outlook) Password Recovery 1.16: PstPassword is a small utility that recovers lost password of Outlook.PST (Personal Folders) file. • Router IP/Passwords: The complete list of Default Router Passwords and Default Router IP Addresses, can be useful if you have misplaced the manual or lost your router password.

• SniffPass 1.12: A password monitoring tool that listens to your network, capture the passwords that pass through your network adapter, it works on POP3, IMAP4, SMTP, FTP, and HTTP protocols and recovers lost Web/FTP/Email passwords. • WebBrowserPassView 1.15: Allows you to view the user names and passwords stored by Mozilla Firefox, Opera, Safari, Google Chrome and Internet explorer Web browsers. • WindowsGate 1.1: Enables/Disables Windows logon password validation.

• WirelessKeyView 1.36: Recovers all wireless network keys (WEP/WPA) stored in your computer by WZC Wireless Zero Configuration. • XP Key Reader 2.7: Can decode the XP-key on Local or Remote systems. • Dependency Walker 2.2: Checks for missing/invalid DLL/modules/functions for any exe/dll/ocx/sys. • IB Process Manager 1.04: a little process manager for 9x/2k, shows dll info etc. • OpenedFilesView 1.52: View opened/locked files in your system, sharing violation issues.

• Pocket KillBox 2.0.0.978: can be used to get rid of files that stubbornly refuse to allow you to delete them. • Process Explorer 15.05: Shows you information about which handles and DLLs processes have opened or loaded. • Process Monitor 2.96: to monitor real-time file system, Registry and process/thread activity, This tool replaces Filemon and Regmon. • ProcessActivityView 1.11: Detailed process access information read/write/opened files etc. • RKill (): RKill just kills malware processes, imports a Registry file that removes incorrect file associations and fixes policies that stop us from using certain tools. • RunAsDate 1.10: allows you to run a program in the date and time that you specify.

• Unlocker 1.9.1: This tool can delete file/folder when you get this message – Cannot delete file: Access is denied, The file is in use by another program etc. • DataRescue DD 1.0: DrDD is a disk imager intended for data recovery and backup of partially corrupted storage devices, the main advantages are Range Selection and Copy Backward Direction. • DiskDigger 0.8.3.176: Undelete and recover lost photos, videos, music, documents and other formats from your hard drive, memory cards and USB flash drives. • DiskGenius 3.2: Restore deleted partition, Rebuild MBR, Rebuild partition table, Recover files, Restore formatted partition, Backup files by partition, Disk clone, Backup partition table, Create/Delete/Format Partitions etc.

• IsoBuster 2.8.5: CD/DVD/Blu-ray and Disk Image File data recovery tool that can read and extract files, tracks and sessions from CD-i, VCD, SVCD, CD-ROM, CD-ROM XA, DVD, DVCD BD and HD DVD and other media as well as a wide variety of disk image formats, it also has retry-mechanisms for damaged CD/DVD. • Partition Find and Mount 2.31: Partition Find and Mount software is designed to find lost or deleted partitions. • PartitionRecovery 1.0: A freeware tool to recover accidentally deleted partitions. • PhotoRec 6.13b: Tool to Recover File and pictures from Dos/Windows/Linux.

• Recuva 1.41.537: Restore deleted files from Hard Drive, Digital Camera Memory Card, usb mp3 player etc. • Restoration 3.2.13: a tool to recover deleted files. • ShadowExplorer 0.8: Shadow Explorer allows you to browse the shadow copies created by the Windows Volume Shadow Copy Service and retrieve older versions from files you accidentally deleted or altered. • Smart Partition Recovery 3.3: Find Lost NTFS partitions and restore them back. • SoftPerfect File Recovery 1.2: to restore accidentally deleted files from hard drive, USB flash drives, CF and SD memory cards. • TestDisk 6.13b: Tool to check and undelete partition from Dos/Windows/Linux. • TrID File Identifier 2.10: Alternative of UnChk and FileChk to recover filetype from the file content.

• Unstoppable Copier 5.2: Allows you to copy files from disks with problems such as bad sectors, scratches or that just give errors when reading data. • ERUNT 1.1j: The Emergency Recovery Utility NT Registry Backup and Restore for Windows NT/2000/2003/XP. • Fix HDC: Fix the Hard Drive Controller when replacing your motherboard on an XP system.

• Glary Registry Repair 3.3.0.852: an advanced registry cleaner that allows you to safely scan, clean, and repair registry problems. • RegFromApp 1.22: Monitors/exports the Registry changes made by the selected application. • Registry Editor PE 0.9c: Easy editing of remote registry hives and user profiles. • Registry Restore Wizard 1.0.4: Restores a corrupted system registry from Xp System Restore. • Regmon 7.04: A monitoring utility that will show you which applications are accessing your Registry. • RegScanner 1.85: Tool to find/search in the Registry of Windows. • RegShot 1.8.2: a registry compare utility that allows you to quickly take a snapshot of your registry and then compare it with a second one – done after doing system changes or installing a new software product.

• Registry Viewer 4.2: Registry Viewer/Editor for Win9x/Me/NT/2K/XP. • Autoruns 11.0: Displays All the entries from startup folder, Run, RunOnce, and other Registry keys, Explorer shell extensions,toolbars, browser helper objects, Winlogon notifications, auto-start services, Scheduled Tasks, Winsock, LSA Providers, Remove Drivers and much more which helps to remove nasty spyware/adware and viruses. • HijackThis 2.0.5b: a general homepage hijackers detector and remover and more. • ServiWin 1.48: Alternative Windows Services/Drivers Tool. • Silent Runners Revision 63: A free script that helps detect spyware, malware and adware in the startup process. • Startup Control Panel 2.8: a tool to edit startup programs. • Startup Monitor 1.02: it notifies you when any program registers itself to run at system startup.

• Astra 5.50: Advanced System info Tool and Reporting Assistant. • BlueScreenView 1.40: Scans minidump files for BSOD (blue screen of death) crash information. • CPU Identification utility 1.20: CHKCPU.EXE Detailed information on CPU. • CPU-Z 1.58: It gathers information on some of the main devices of your system. • CTIA CPU Information 2.7: another CPU information tool. • Drive Temperature 1.0: Hard Disk Drive temperature meter. • GPU-Z 0.5.5: A lightweight utility designed to give you all information about your video card and GPU.

• HWiNFO 5.5.2: a powerful system information utility. • Navratil Software System Information 0.60.45: High-end professional system information tool.

• PCI and AGP info Tool (): The PCI System information and Exploration tool. • PC Wizard 2010.1.961: PCWizard is a powerful system information/benchmark utility designed especially for detection of hardware. • SIW 2011.09.16: Gathers detailed information about your system properties and settings. • Speccy 1.13.276: an advanced System Information tool for your PC. • System Analyser 5.3w: View extensive information about your hardware. • System Explorer 3.0.6: Shows detailed system information about processes, startups, IE addons, drivers, explorer, etc.

• SysChk 2.46: Find out exactly what is under the hood of your PC. • Update Checker 1.038: scans your computer for installed software and checks for newer releases on FileHippo.

• Bart’s Stuff Test 5.1.4: Long term heavy stress testing storage devices. • CPU/Video/Disk Performance Test 5.7: a tool to test cpu, video, and disk. • Disk Speed 1.0: Hard Disk Drive Speed Testing Tool. • GoldMemory 5.07: Memory Diagnostic Tests. • H2testw 1.4: Check your USB Flash memory cards, internal/external hard drives and network drives for errors with this tool.

• HDD Scan 2.8: HDDScan is a Low-level HDD diagnostic tool, it scans surface find bad sectors etc. • IsMyLcdOK (Monitor Test) 1.02: Allows you to test CRT/LCD/TFT screens for dead pixels and diffective screens. • Memtest86+ 4.20: PC Memory Test. • MemTest 1.0: a Memory Testing Tool. • Prime95 25.11: This will detect for errors in CPU or RAM within a matter of minutes if an overclock is not stable, you can run Torture Test (burn-in) overnight to ensure long-term stability of the hardware. • S&M Stress Test 1.9.1: cpu/hdd/memory benchmarking and information tool, including temperatures/fan speeds/voltages.

• System Speed Test 4.78: it tests CPU, harddrive, ect. • Test Hard Disk Drive 1.0: a tool to test Hard Disk Drive. • Video Memory Stress Test 1.7.116: a tool to thoroughly test your video RAM for errors and faults. • Video Memory Stress Test CE 1.21: Tests all video RAM accessible by 32-bit CPU address space from a clean environment. • Windows Memory Diagnostic: a RAM Test tool.

• Dial a Fix 0.60.0.24: Fix errors and problems with COM/ActiveX object errors and missing registry entries, Automatic Updates, SSL, HTTPS, and Cryptography service (signing/verification) issues, Reinstall internet explorer etc. Comes with the policy scanner.

• Disable Autorun: A small tweak which disables processing of autorun.inf to protect your PC from usb autorun viruses. • Disable Compress Old Files: This registry tweak is useful when Disk Cleanup Tool Stops Responding While Compressing Old Files.

• EzPcFix 1.0.0.16: Helpful tool when trying to remove viruses, spyware, and malware. • FileTypesMan 1.61: File Types Manager for Windows to add, edit, and remove actions in the properties and flags of each file type. • InstalledCodec 1.25: Disable/Enable Installed Codec drivers and DirectShow filters. • KeyTweak 2.3.0: a program to Remap Keyboard Layout, you can even customize a broken key to an unused key.

• Protect a Drive from Autorun Virus: Protect your pen drive from being infected when you plug it in an infected PC. • RemoveWGA 1.2: Windows Genuine Advantage Notifications Removal tool. • RRT – Remove Restrictions Tool 3.0: to Re-enable Ctrl+Alt+Del, Folder Options and Registry tools etc. • Shell Extensions Manager (ShellExView) 1.66: An excellent tool to View and Manage all installed Context-menu/Shell extensions. • ShellMenuNew 1.01: View/Change the list of all menu items in the ‘New’ submenu of Windows Explorer. • Show Hidden Devices: Device Manager hides nonpresent devices that are not physically present in the system, but still have configuration information in the Registry.

• TweakUI 2.10: This PowerToy gives you access to system settings that are not exposed in Windows Xp. • Ultimate Windows Tweaker 2.2: A TweakUI Utility for tweaking and optimizing Windows Vista. • Write Protect USB Devices: Tweak your PC to make USB Pen Drive, Memory Card or Thumb Drive as Read Only. • Xp-AntiSpy 3.97.11: it tweaks some Windows XP functions, and disables some unneeded Windows services quickly.

HP Client Management Solutions help simplify management of Workstations and significantly reduce total ownership costs. These solutions share a common design and are highly integrated. HP Client Manager Software is included free with all HP business PCs and Workstations. A Keyboard Driver is software which allows communication between your keyboard and your PC or laptop.

If your keyboard does not work at all, first make sure it is plugged into your computer correctly. Most keyboards connect via a USB port or a PS/2 port. Try plugging it into a different port. Wireless keyboards need special drivers to work properly, and connect via a Bluetooth interface. If Windows still does not recognize your Keyboard, your Keyboard Driver might be missing, corrupted or need to be updated. To check, open Device Manager (you may be asked for an admin password). If you see a yellow question mark next to the name of the keyboard in Device Manager, there might be a problem.

If you have had recent power outages, viruses, or other computer problems, it is likely that the drivers have become damaged. Downloading and installing the latest driver can resolve these types of problems. And solve your driver problems instantly or to find the exact Keyboard driver that fits your needs. Sometimes I get calls from the helpdesk staff asking about the Windows Resume Loader issue. It happens with Windows 7 or Vista OS computers during the startup process when the black Resume Loader screen appears with the following message: “The last attempt to resume the system from its previous location failed.

Attempt to resume again? (Use arrow keys to highlight your choice.) 1. Continue with system resume 2.

Delete restoration data and proceed to system boot menu ENTER=Choose” It happens during the unexpected PC shut down due to a sudden power failure, especially when the machine is in a hibernation mode. During the next boot up the system uses the resume loader to return from hibernation and attempts to load a hibernation file (hiberfil.sys) that could be corrupted. That’s when a black screen appears with the strange resume loader message. We have two options: 1. Press “continue with system resume”. If the hibernation file is still intact, the system will resume and load up. If that doesn’t help, proceed to step 2 2.

Select the second option to “Delete restoration data” The damaged hiberfil.sys file will be deleted and your computer will boot up, but any data that was stored in a hibernation file during the hibernation process will be lost. However, you will be able to start up your Windows system. There is one more thing some of us could be dealing with – unresponsive keyboard.

You may be seeing the resume loader options, but your keyboard may not be active, so you really can’t change anything at this point. If your keyboard and motherboard connections are fine (check them anyway), follow the advice below.

There is one pretty simple trick: restart your computer and enter your BIOS settings. (Press Del, F2, F1, F5, F12 or any other key assigned for that purpose by your computer manufacturer). Once you access BIOS go to Peripherals section, scroll down to “USB keyboard” section and make sure that it is enabled, not disabled. I had the same problem twice (both times power failure) and fixed it by enabling the keyboard. I don’t really know why it’s set to disabled every time the power goes out. If that doesn’t help there is one more remedy: open PC case and unplug the CMOS battery for a few minutes. Modern Problems In Classical Electrodynamics Djvu more.

Put it back, close the case and start the PC. Reset your date, floppy drive settings in BIOS and start the operational system. That should do. Update: For some people the methods described above don’t work, so you can try these: • Unplug the power cord from the PC and press the power button for 15 – 20 sec.

This will reset your capacitors. Plug the cord back in and start the PC.

Your keyboard should be working. • If your keyboard is still unresponsive, borrow from someone the PS/2 keyboard (not USB keyboard), plug it in and start the PC. The keyboard should be working. • For laptop users: take out your laptop battery, unplug the power cord and then press the power button for 15 sec.

To reset the capacitors. Then plug in the power cord, but don’t put your battery back in yet. See if that fixes the unresponsive keyboard. If everything is Rock&Roll, plug in your battery.

• If nothing helps to resume your Windows, there’s one more solution: load the Ubuntu live CD and enable your keyboard during the live session. Ubuntu uses its own hardware drivers, that’s why the keyboard will be working. I heard that some people were lucky to come up with that trick. • 0.5 A (USB 2.0) • 0.9 A (USB 3.0) • 5 A ( BC 1.2) • 3 A (type-C) • Up to 5 A ( PD) Data Data signal Packet data, defined by specifications Width 1 bit Bitrate 1.5, 12, 480, 5,000, 10,000 (depending on mode) Max. Devices 127 Protocol Pin out The type-A plug (left) and type-B plug (right) Pin 1 V BUS (+5 V) Pin 2 Data− Pin 3 Data+ Pin 4 Ground USB, short for Universal Serial Bus, is an that defines cables, connectors and for connection, communication, and power supply between and electronic devices. USB was designed to standardize the connection of (including keyboards,, digital cameras, printers,, and ) to, both to communicate and to supply. It has largely replaced a variety of earlier interfaces, such as and, as well as separate for portable devices - and has become commonplace on a wide range of devices.

Initially developed in the mid-1990s, it is currently developed by the (USB IF). • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • Overview [ ] In general, there are three basic formats of USB connectors: the default or standard format intended for desktop or portable equipment (for example, on USB ), the mini intended for mobile equipment (now deprecated except the Mini-B, which is used on many cameras), and the thinner micro size, for low-profile mobile equipment (most modern mobile phones). Also, there are 5 modes of USB data transfer, in order of increasing bandwidth: Low Speed (from 1.0), Full Speed (from 1.0), High Speed (from 2.0), (from 3.0), and SuperSpeed+ (from 3.1); modes have differing hardware and cabling requirements.

USB devices have some choice of implemented modes, and USB version is not a reliable statement of implemented modes. Modes are identified by their names and icons, and the specifications suggests that plugs and receptacles be colour-coded (SuperSpeed is identified by blue). Unlike other data buses (e.g., Ethernet, HDMI), USB connections are directed, with both upstream and downstream ports emanating from a single host. This applies to electrical power, with only downstream facing ports providing power; this topology was chosen to easily prevent electrical overloads and damaged equipment. Thus, USB cables have different ends: A and B, with different physical connectors for each. Therefore, in general, each different format requires four different connectors: a plug and receptacle for each of the A and B ends.

USB cables have the plugs, and the corresponding receptacles are on the computers or electronic devices. In common practice, the A end is usually the standard format, and the B side varies over standard, mini, and micro. The mini and micro formats also provide for with a hermaphroditic AB receptacle, which accepts either an A or a B plug.

On-the-Go allows USB between peers without discarding the directed topology by choosing the host at connection time; it also allows one receptacle to perform double duty in space-constrained applications. There are cables with A plugs on both ends, which may be valid if the cable includes, for example, a USB host-to-host transfer device with 2 ports, but they could also be non-standard and erroneous and should be used carefully. The micro format is the most durable from the point of view of designed insertion lifetime. The standard and mini connectors have a design lifetime of 1,500 insertion-removal cycles, the improved Mini-B connectors increased this to 5,000.

The micro connectors were designed with frequent charging of portable devices in mind, so have a design life of 10,000 cycles and also place the flexible contacts, which wear out sooner, on the easily replaced cable, while the more durable rigid contacts are located in the receptacles. Likewise, the springy component of the retention mechanism, parts that provide required gripping force, were also moved into plugs on the cable side. USB logo on the head of a standard A plug (the most common ) A group of seven companies began the development of USB in 1994:,,,,,, and. The goal was to make it fundamentally easier to connect external devices to PCs by replacing the multitude of connectors at the back of PCs, addressing the usability issues of existing interfaces, and simplifying software configuration of all devices connected to USB, as well as permitting greater data rates for external devices. A team including worked on the standard at Intel; the first supporting USB were produced by Intel in 1995. The original USB 1.0 specification, which was introduced in January 1996, defined data transfer rates of 1.5 Low Speed and 12 Mbit/s Full Speed.

Microsoft provided OEM support for the devices. The first widely used version of USB was 1.1, which was released in September 1998. The 12 Mbit/s data rate was intended for higher-speed devices such as disk drives, and the lower 1.5 Mbit/s rate for low data rate devices such as. 's was the first mainstream product with USB and the iMac's success popularized USB itself. Following Apple's design decision to remove all from the iMac, many PC manufacturers began building, which led to the broader PC market using USB as a standard. The USB 2.0 specification was released in April 2000 and was ratified by the (USB-IF) at the end of 2001., Intel, (now Nokia), NEC, and jointly led the initiative to develop a higher data transfer rate, with the resulting specification achieving 480 Mbit/s, a 40-times increase over the original USB 1.1 specification. The USB 3.0 specification was published on 12 November 2008.

Its main goals were to increase the data transfer rate (up to 5 Gbit/s), decrease power consumption, increase power output, and be with USB 2.0. USB 3.0 includes a new, higher speed bus called SuperSpeed in parallel with the USB 2.0 bus. For this reason, the new version is also called SuperSpeed. The first USB 3.0 equipped devices were presented in January 2010. As of 2008, approximately 6 billion USB ports and interfaces were in the global marketplace, and about 2 billion were being sold each year.

In December 2014, USB-IF submitted USB 3.1, USB Power Delivery 2.0 and specifications to the ( – Audio, video and multimedia systems and equipment) for inclusion in the international standard IEC 62680 Universal Serial Bus interfaces for data and power, which is currently based on USB 2.0. USB 2.0 was released in April 2000, adding a higher maximum of 480 Mbit/s ( High Speed or High Bandwidth), in addition to the USB 1.x Full Speed signaling rate of 12 Mbit/s. Due to bus access constraints, the effective throughput of the High Speed signaling rate is limited to 280 Mbit/s or 35 MB/s. Further modifications to the USB specification have been made via (ECN). The most important of these ECNs are included into the USB 2.0 specification package available from USB.org: • Mini-A and Mini-B Connector ECN: Released in October 2000.

Specifications for Mini-A and Mini-B plug and receptacle. Also receptacle that accepts both plugs for On-The-Go. These should not be confused with Micro-B plug and receptacle. • Pull-up/Pull-down Resistors ECN: Released in May 2002 • Interface Associations ECN: Released in May 2003. New standard descriptor was added that allows associating multiple interfaces with a single device function.

• Rounded Chamfer ECN: Released in October 2003. A recommended, backward compatible change to Mini-B plugs that results in longer lasting connectors.

• Unicode ECN: Released in February 2005. This ECN specifies that strings are encoded using.

USB 2.0 specified, but did not specify the encoding. • Inter-Chip USB Supplement: Released in March 2006 • On-The-Go Supplement 1.3: Released in December 2006. Makes it possible for two USB devices to communicate with each other without requiring a separate USB host. In practice, one of the USB devices acts as a host for the other device.

• Battery Charging Specification 1.1: Released in March 2007 and updated on 15 April 2009. Adds support for dedicated chargers (power supplies with USB connectors), host chargers (USB hosts that can act as chargers) and the No Dead Battery provision, which allows devices to temporarily draw 100 mA current after they have been attached. If a USB device is connected to a dedicated charger, maximum current drawn by the device may be as high as 1.8 A. (Note that this document is not distributed with USB 2.0 specification package, only USB 3.0 and USB On-The-Go.) • Micro-USB Cables and Connectors Specification 1.01: Released in April 2007. • Link Power Management Addendum ECN: Released in July 2007. This adds sleep, a new power state between enabled and suspended states. Device in this state is not required to reduce its power consumption.

However, switching between enabled and sleep states is much faster than switching between enabled and suspended states, which allows devices to sleep while idle. • Battery Charging Specification 1.2: Released in December 2010.

Several changes and increasing limits including allowing 1.5 A on charging ports for unconfigured devices, allowing High Speed communication while having a current up to 1.5 A and allowing a maximum current of 5 A. The USB 3.0 specification was released on 12 November 2008, with its management transferring from USB 3.0 Promoter Group to the USB Implementers Forum (USB-IF), and announced on 17 November 2008 at the SuperSpeed USB Developers Conference. USB 3.0 defines a new SuperSpeed transfer mode, with associated new backward compatible plugs, receptacles, and cables. SuperSpeed plugs and receptacles are identified with a distinct logo and blue inserts in standard format receptacles. The new SuperSpeed mode provides a of 5.0 Gbit/s. However, due to the overhead incurred by, the payload throughput is actually 4 Gbit/s, and the specification considers it reasonable to achieve only around 3.2 Gbit/s (0.4 GB/s or 400 MB/s). However, this should increase with future hardware advances.

Communication is in SuperSpeed transfer mode; earlier modes are half-duplex, arbitrated by the host. Low-power and high-power devices remain operational with this standard, but devices using SuperSpeed can take advantage of increased available current of between 150 mA and 900 mA, respectively.

Additionally, there is a Battery Charging Specification (Version 1.2 – December 2010), which increases the power handling capability to 1.5 A but does not allow concurrent data transmission. The Battery Charging Specification requires that the physical ports themselves be capable of handling 5 A of current [ ] but limits the maximum current drawn to 1.5 A. USB 3.1 [ ] A January 2013 press release, from the USB group revealed plans to update USB 3.0 to 10 Gbit/s. The group ended up creating a new USB specification, USB 3.1, which was released on 31 July 2013, replacing the USB 3.0 standard. The USB 3.1 specification takes over the existing USB 3.0's SuperSpeed USB transfer rate, also referred to as USB 3.1 Gen 1, and introduces a faster transfer rate called SuperSpeed USB 10 Gbps, also referred to as USB 3.1 Gen 2, putting it on par with a single first-generation channel.

The new mode's logo features a caption stylized as SUPER SPEED+. The USB 3.1 Gen 2 standard increases the to 10 Gbit/s, double that of SuperSpeed USB, and reduces line encoding overhead to just 3% by changing the to. The first USB 3.1 Gen 2 implementation demonstrated transfer speeds of 7.2 Gbit/s. The USB 3.1 standard is backward compatible with USB 3.0 and USB 2.0. System design [ ] The design architecture of USB is in its topology, consisting of a, a multitude of downstream USB ports, and multiple connected in a tiered.

Additional may be included in the tiers, allowing branching into a tree structure with up to five tier levels. A USB host may implement multiple host controllers and each host controller may provide one or more USB ports. Up to 127 devices, including hub devices if present, may be connected to a single host controller. USB devices are linked in series through hubs.

One hub—built into the host controller—is the root hub. A physical USB device may consist of several logical sub-devices that are referred to as device functions. A single device may provide several functions, for example, a (video device function) with a built-in microphone (audio device function). This kind of device is called a composite device. An alternative to this is, in which the host assigns each logical device a distinctive address and all logical devices connect to a built-in hub that connects to the physical USB cable. USB endpoints actually reside on the connected device: the channels to the host are referred to as pipes USB device communication is based on pipes (logical channels). A pipe is a connection from the host controller to a logical entity, found on a device, and named an.

Because pipes correspond 1-to-1 to endpoints, the terms are sometimes used interchangeably. A USB device could have up to 32 endpoints (16 IN, 16 OUT), though it's rare to have so many. An endpoint is defined and numbered by the device during initialization (the period after physical connection called 'enumeration') and so is relatively permanent, whereas a pipe may be opened and closed. There are two types of pipe: stream and message. A message pipe is bi-directional and is used for control transfers. Message pipes are typically used for short, simple commands to the device, and a status response, used, for example, by the bus control pipe number 0.

Two USB 3.0 standard A sockets (left) and two USB 2.0 sockets (right) on a computer's front panel Endpoints are grouped into interfaces and each interface is associated with a single device function. An exception to this is endpoint zero, which is used for device configuration and is not associated with any interface. A single device function composed of independently controlled interfaces is called a composite device. A composite device only has a single device address because the host only assigns a device address to a function. When a USB device is first connected to a USB host, the USB device enumeration process is started. The enumeration starts by sending a reset signal to the USB device.

The data rate of the USB device is determined during the reset signaling. After reset, the USB device's information is read by the host and the device is assigned a unique 7-bit address. If the device is supported by the host, the needed for communicating with the device are loaded and the device is set to a configured state. If the USB host is restarted, the enumeration process is repeated for all connected devices. The host controller directs traffic flow to devices, so no USB device can transfer any data on the bus without an explicit request from the host controller. In USB 2.0, the host controller the bus for traffic, usually in a fashion.

The throughput of each USB port is determined by the slower speed of either the USB port or the USB device connected to the port. High-speed USB 2.0 hubs contain devices called transaction translators that convert between high-speed USB 2.0 buses and full and low speed buses. When a high-speed USB 2.0 hub is plugged into a high-speed USB host or hub, it operates in high-speed mode.

The USB hub then uses either one transaction translator per hub to create a full/low-speed bus routed to all full and low speed devices on the hub, or uses one transaction translator per port to create an isolated full/low-speed bus per port on the hub. Because there are two separate controllers in each USB 3.0 host, USB 3.0 devices transmit and receive at USB 3.0 data rates regardless of USB 2.0 or earlier devices connected to that host. Operating data rates for earlier devices are set in the legacy manner.

Device classes [ ] The functionality of USB devices is defined by class codes, communicated to the USB host to affect the loading of suitable software driver modules for each connected device. This provides for adaptability and device independence of the host to support new devices from different manufacturers. Device classes include: Class Usage Description Examples, or exception 00 Device Unspecified Device class is unspecified, interface descriptors are used to determine needed drivers 01h Interface Audio,,, 02h Both,, adapter,. Circuit board from a USB 3.0 external 2.5-inch SATA HDD enclosure USB implements connections to storage devices using a set of standards called the (MSC or UMS). This was at first intended for traditional magnetic and optical drives and has been extended to support.

It has also been extended to support a wide variety of novel devices as many systems can be controlled with the familiar metaphor of file manipulation within directories. The process of making a novel device look like a familiar device is also known as extension. The ability to boot a write-locked with a USB adapter is particularly advantageous for maintaining the integrity and non-corruptible, pristine state of the booting medium. Though most computers since mid-2004 can boot from USB mass storage devices, USB is not intended as a primary bus for a computer's internal storage. Buses such as (PATA or IDE), (SATA), or fulfill that role in PC class computers. However, USB has one important advantage, in that it is possible to install and remove devices without rebooting the computer (), making it useful for mobile peripherals, including drives of various kinds (given SATA or SCSI devices may or may not support hot-swapping).

Firstly conceived and still used today for optical storage devices ( drives, drives, etc.), several manufacturers offer external portable USB, or empty enclosures for disk drives. These offer performance comparable to internal drives, limited by the current number and types of attached USB devices, and by the upper limit of the USB interface (in practice about 30 MB/s for USB 2.0 and potentially 400 MB/s or more for USB 3.0).

These external drives typically include a 'translating device' that bridges between a drive's interface to a USB interface port. Functionally, the drive appears to the user much like an internal drive.

Other competing standards for external drive connectivity include,, (IEEE 1394), and most recently. Another use for USB mass storage devices is the portable execution of software applications (such as web browsers and VoIP clients) with no need to install them on the host computer. Media Transfer Protocol [ ] (MTP) was designed by to give higher-level access to a device's filesystem than USB mass storage, at the level of files rather than disk blocks. It also has optional features. MTP was designed for use with, but it has since been adopted as the primary storage access protocol of the from the version 4.1 Jelly Bean as well as Windows Phone 8 (Windows Phone 7 devices had used the Zune protocol which was an evolution of MTP).

The primary reason for this is that MTP does not require exclusive access to the storage device the way UMS does, alleviating potential problems should an Android program request the storage while it is attached to a computer. The main drawback is that MTP is not as well supported outside of Windows operating systems. Human interface devices [ ] Joysticks, keypads, tablets and other human-interface devices (HIDs) are also progressively [ ] migrating from MIDI, and PC connectors to USB. [ ] USB mice and keyboards can usually be used with older computers that have with the aid of a small USB-to-PS/2 adapter. For mice and keyboards with dual-protocol support, an adaptor that contains no may be used: the hardware in the USB keyboard or mouse is designed to detect whether it is connected to a USB or PS/2 port, and communicate using the appropriate protocol. Converters also exist that connect PS/2 keyboards and mice (usually one of each) to a USB port. These devices present two HID endpoints to the system and use a to perform bidirectional data translation between the two standards.

Device Firmware Upgrade [ ] Device Firmware Upgrade (DFU) is a vendor- and device-independent mechanism for upgrading the of USB devices with improved versions provided by their manufacturers, offering (for example) a way for firmware bugfixes to be deployed. During the firmware upgrade operation, USB devices change their operating mode effectively becoming a programmer. Any class of USB device can implement this capability by following the official DFU specifications. In addition to its intended legitimate purposes, DFU can also be exploited by uploading maliciously crafted firmwares that cause USB devices to spoof various other device types; one such exploiting approach is known as. Connectors [ ] Connector properties [ ]. Type-A plug and, as part of a non-standard cable, receptacle The connectors the USB committee specifies support a number of USB's underlying goals, and reflect lessons learned from the many connectors the computer industry has used.

Receptacles and plugs [ ] The connector mounted on the host or device is called the receptacle, and the connector attached to the cable is called the plug. The official USB specification documents also periodically define the term male to represent the plug, and female to represent the receptacle. Usability and orientation [ ]. By design, it is difficult to insert a USB plug into its receptacle incorrectly.

The USB specification states that the required USB icon must be embossed on the 'topside' of the USB plug, which '.provides easy user recognition and facilitates alignment during the mating process.' The specification also shows that the 'recommended' 'Manufacturer's logo' ('engraved' on the diagram but not specified in the text) is on the opposite side of the USB icon. The specification further states, 'The USB Icon is also located adjacent to each receptacle.

Receptacles should be oriented to allow the icon on the plug to be visible during the mating process.' However, the specification does not consider the height of the device compared to the eye level height of the user, so the side of the cable that is 'visible' when mated to a computer on a desk can depend on whether the user is standing or kneeling. While connector interfaces can be designed to allow plugging with either orientation, the original design omitted such functionality to decrease manufacturing costs.

The reversible type-C plug is an addition to the specification comparable in size to the Micro-B SuperSpeed connector. Only moderate force is needed to insert or remove a USB cable. USB cables and small USB devices are held in place by the gripping force from the receptacle (without need of the screws, clips, or thumb-turns other connectors have required). Power-use topology [ ] The standard connectors were deliberately intended to enforce the directed of a USB network: type-A receptacles on host devices that supply power and type-B receptacles on target devices that draw power. This prevents users from accidentally connecting two USB power supplies to each other, which could lead to and dangerously high currents, circuit failures, or even fire. USB does not support cyclic networks and the standard connectors from incompatible USB devices are themselves incompatible. However, some of this directed topology is lost with the advent of multi-purpose USB connections (such as in smartphones, and USB-powered Wi-Fi routers), which require A-to-A, B-to-B, and sometimes Y/splitter cables.

See the section below for a more detailed summary description. Durability [ ] The standard connectors were designed to be more robust than many past connectors. This is because USB is, and the connectors would be used more frequently, and perhaps with less care, than previous connectors. Standard USB has a minimum rated lifetime of 1,500 cycles of insertion and removal, the the mini-USB receptacle increases this to 5,000 cycles, and the newer Micro-USB and USB-C receptacles are both designed for a minimum rated lifetime of 10,000 cycles of insertion and removal.

To accomplish this, a locking device was added and the leaf-spring was moved from the jack to the plug, so that the most-stressed part is on the cable side of the connection. This change was made so that the connector on the less expensive cable would bear the most wear. In standard USB, the electrical contacts in a USB connector are protected by an adjacent plastic tongue, and the entire connecting assembly is usually protected by an enclosing metal sheath. In all USB connectors, the construction always ensures that the external sheath on the plug makes contact with its counterpart in the receptacle before any of the four connectors within make electrical contact. The external metallic sheath is typically connected to system ground, thus dissipating damaging static charges. This enclosure design also provides a degree of protection from electromagnetic interference to the USB signal while it travels through the mated connector pair (the only location when the otherwise travels in parallel).

In addition, because of the required sizes of the power and common connections, they are made after the system ground but before the data connections. This type of staged make-break timing allows for electrically safe hot-swapping. Compatibility [ ] The USB standard specifies relatively loose tolerances for compliant USB connectors to minimize physical incompatibilities in connectors from different vendors.

To address a weakness present in some other connector standards, the USB specification also defines limits to the size of a connecting device in the area around its plug. This was done to prevent a device from blocking adjacent ports due to the size of the cable strain relief mechanism (usually molding integral with the cable outer insulation) at the connector. Compliant devices must either fit within the size restrictions or support a compliant extension cable that does. In general, USB cables have only plugs on their ends, while hosts and devices have only receptacles. Hosts almost universally have Type-A receptacles, while devices have one or another Type-B variety.

Type-A plugs mate only with Type-A receptacles, and the same applies to their Type-B counterparts; they are deliberately physically incompatible. However, an extension to the USB standard specification called (OTG) allows a single port to act as either a host or a device, which is selectable by the end of the cable that plugs into the receptacle on the OTG-enabled unit. Even after the cable is hooked up and the units are communicating, the two units may 'swap' ends under program control.

This capability is meant for units such as in which the USB link might connect to a PC's host port as a device in one instance, yet connect as a host itself to a keyboard and mouse device in another instance. Connector types [ ]. • is a proprietary non-USB connector. • Upside down, so the contacts are visible. There are several types of USB connector, including some that have been added while the specification progressed. The original USB specification detailed standard-A and standard-B plugs and receptacles; the B connector was necessary so that cabling could be plug ended at both ends and still prevent users from connecting one computer receptacle to another.

The first engineering change notice to the USB 2.0 specification added Mini-B plugs and receptacles. The data pins in the standard plugs are actually recessed in the plug compared to the outside power pins. This permits the power pins to connect first, preventing data errors by allowing the device to power up first and then establish the data connection. Also, some devices operate in different modes depending on whether the data connection is made. To reliably enable a charge-only feature, modern USB accessory peripherals now include charging cables that provide power connections to the host port but no data connections, and both home and vehicle charging docks are available that supply power from a converter device and do not include a host device and data pins, allowing any capable USB device to charge or operate from a standard USB cable. In a charge-only cable, the data wires are shorted at the device end. These wires are usually green and white.

If these wires are left as-is, the device will often reject the charger as unsuitable. Standard connectors [ ]. Pin configuration of the type-A and type-B USB connectors, viewed from the mating (male) end of plugs The type-A plug has an elongated rectangular cross-section, inserts into a type-A receptacle on a downstream port on a USB host or hub, and carries both power and data. Captive cables on USB devices, such as keyboards or mice, will be terminated with a type-A plug. The type-B plug has a near square cross-section with the top exterior corners beveled. As part of a removable cable, it inserts into an upstream port on a device, such as a printer. On some devices, the type-B receptacle has no data connections, being used solely for accepting power from the upstream device.

This two-connector-type scheme (A/B) prevents a user from accidentally creating a loop. The spring contacts in the connectors eventually relax and wear out with repeated cycles of plugging and unplugging. The lifetime of a type-A plug is approximately 1,500 connect/disconnect cycles. The maximum allowed cross-section of the overmold boot (which is part of the connector used for its handling) is 16 by 8 mm for the standard-A plug type, while for the type-B it is 11.5 by 10.5 mm. Mini connectors [ ].

Mini-A (left) and Mini-B (right) plugs For smaller devices such as,, and, various smaller connectors have been used – the USB-standard first introduced the Mini-USB connectors in April 2000. Mini-USB connectors were introduced with USB 2.0 in April 2000 – however the Mini-A connector and the Mini-AB receptacle connector are (i.e. De-certified, but standardized) since May 2007. Mini-B connectors are still supported, but are not On-The-Go-compliant; the Mini-B USB connector was standard for transferring data to and from the early smartphones and PDAs. Both Mini-A and Mini-B plugs are approximately 3 by 7 mm. Micro connectors [ ].

Micro-B plug Micro-USB connectors, which were announced by the on 4 January 2007, have a similar width to Mini-USB, but approximately half the thickness, enabling their integration into thinner portable devices. The Micro-A connector is 6.85 by 1.8 with a maximum overmold boot size of 11.7 by 8.5 mm, while the Micro-B connector is 6.85 by 1.8 mm with a maximum overmold size of 10.6 by 8.5 mm. The thinner Micro-USB connectors were introduced to replace the Mini connectors in devices manufactured since May 2007, including,, and cameras. While some of the devices and cables still use the older Mini variant, the newer Micro connectors are widely adopted, and as of December 2010 they are the most widely used. [ ] The Micro plug design is rated for at least 10,000 connect-disconnect cycles, which is more than the Mini plug design. The Micro connector is also designed to reduce the mechanical wear on the device; instead the easier-to-replace cable is designed to bear the mechanical wear of connection and disconnection. The Universal Serial Bus Micro-USB Cables and Connectors Specification details the mechanical characteristics of Micro-A, Micro-AB receptacles (which accept both Micro-A and Micro-B plugs), and Micro-B plugs and receptacles, along with a standard-A receptacle to Micro-A plug adapter.

OMTP standard [ ] Micro-USB was endorsed as the standard connector for data and power on mobile devices by the cellular phone carrier group (OMTP) in 2007. Micro-USB was embraced the 'Universal Charging Solution' by the (ITU) in October 2009. In Europe, micro-USB became the defined (EPS) for use with smartphones sold in the EU, 14 of the world's largest mobile phone manufacturers signed the EU's common EPS Memorandum of Understanding (MoU)., one of the original MoU signers, makes Micro-USB adapters available – as permitted in the Common EPS MoU – for its equipped with Apple's proprietary or (later).

Accrding to the, and. Non-standard cables [ ].

USB 3.0 Micro-B SuperSpeed plug USB 3.0 introduced Type-A SuperSpeed plugs and receptacles as well as micro-sized Type-B SuperSpeed plugs and receptacles. The 3.0 receptacles are backward-compatible with the corresponding pre-3.0 plugs. USB 3.0 and USB 1.0 Type-A plugs and receptacles are designed to interoperate. In order to achieve USB 3.0's SuperSpeed (and SuperSpeed+ for USB 3.1 Gen 2), 5 extra pins are added to the unused area of the original 4 pin USB 1.0 design, making USB 3.0 Type-A plugs and receptacles backward compatible to those of USB 1.0. USB Micro-B USB 2.0 vs USB Micro-B SuperSpeed (USB 3.0) On the device side, a modified Micro-B plug (Micro-B SuperSpeed) is used to cater for the 5 extra pins required to achieve the USB 3.0 features (USB Type-C plug can also be used). The USB 3.0 Micro-B plug effectively consists of a standard USB 2.0 Micro-B cable plug, with an additional 5 pins plug 'stacked' to the side of it.

In this way, cables with smaller 5 pin USB 2.0 Micro-B plugs can be plugged into devices with 10 contact USB 3.0 Micro-B receptacles and achieve backward compatibility. USB cables exist with various combinations of plugs on each end of the cable, as displayed below in the USB cables matrix. USB On-The-Go connectors [ ] (OTG) introduces the concept of a device performing both master and slave roles. All current OTG devices are required to have one, and only one, USB connector: a Micro-AB receptacle. (In the past, before the development of Micro-USB, On-The-Go devices used Mini-AB receptacles). The Micro-AB receptacle is capable of accepting both Micro-A and Micro-B plugs, attached to any of the legal cables and adapters as defined in revision 1.01 of the Micro-USB specification.

To enable Type-AB receptacles to distinguish which end of a cable is plugged in, plugs have an 'ID' pin in addition to the four contacts found in standard-size USB connectors. This ID pin is connected to GND in Type-A plugs, and left unconnected in Type-B plugs. Typically, a in the device is used to detect the presence or absence of an ID connection. The OTG device with the A-plug inserted is called the A-device and is responsible for powering the USB interface when required, and by default assumes the role of host.

The OTG device with the B-plug inserted is called the B-device and by default assumes the role of peripheral. An OTG device with no plug inserted defaults to acting as a B-device. If an application on the B-device requires the role of host, then the Host Negotiation Protocol (HNP) is used to temporarily transfer the host role to the B-device. OTG devices attached either to a peripheral-only B-device or a standard/embedded host have their role fixed by the cable, since in these scenarios it is only possible to attach the cable one way. Developed at roughly the same time as the USB 3.1 specification, but distinct from it, the USB Type-C Specification 1.0 was finalized in August 2014 and defines a new small reversible-plug connector for USB devices. The Type-C plug connects to both hosts and devices, replacing various Type-A and Type-B connectors and cables with a standard meant to be future-proof. The 24-pin double-sided connector provides four power-ground pairs, two differential pairs for USB 2.0 data bus (though only one pair is implemented in a Type-C cable), four pairs for SuperSpeed data bus (only two pairs are used in USB 3.1 mode), two 'sideband use' pins, V CONN +5 V power for active cables, and a configuration pin for cable orientation detection and dedicated (BMC) configuration data channel.

Type-A and Type-B adaptors and cables are required for older devices to plug into Type-C hosts. Adapters and cables with a Type-C receptacle are not allowed. Full-featured USB 3.1 Type-C cables are electronically marked cables that contain a full set of wires and a chip with an ID function based on the configuration data channel and vendor-defined messages (VDMs) from the specification. USB Type-C devices also support power currents of 1.5 A and 3.0 A over the 5 V power bus in addition to baseline 900 mA; devices can either negotiate increased USB current through the configuration line, or they can support the full Power Delivery specification using both BMC-coded configuration line and legacy BFSK-coded V BUS line.

Alternate Mode dedicates some of the physical wires in the USB-C cable for direct device-to-host transmission of alternate data protocols. [ ] The four high-speed lanes, two sideband pins, and‍—‌for dock, detachable device and permanent cable applications only‍—‌two USB 2.0 pins and one configuration pin can be used for Alternate Mode transmission. The modes are configured using VDMs through the configuration channel.

Host and device interface receptacles [ ] USB plugs fit one receptacle with notable exceptions for USB On-The-Go 'AB' support and the general backward compatibility of as shown. Non-standard Existing for specific, and in most cases not inter-operable with USB-IF compliant equipment. In addition to the above cable assemblies comprising two plugs, an 'adapter' cable with a Micro-A plug and a standard-A receptacle is compliant with USB specifications. Other combinations of connectors are not compliant. There do exist A-to-A assemblies, referred to as cables (such as the ); however, these have a pair of USB devices in the middle, making them more than just cables.

Some older devices and cables with Mini-A connectors have been certified by USB-IF. The Mini-A connector is obsolete: no new Mini-A connectors and neither Mini-A nor Mini-AB receptacles will be certified.

Note: Mini-B is not deprecated, but less and less used since the arrival of Micro-B. Pinouts [ ] USB is a serial bus, using four shielded wires for the USB 2.0 variant: two for power (V BUS and GND), and two for (labelled as D+ and D− in ).

(NRZI) encoding scheme is used for transferring data, with a sync field to synchronize the host and receiver clocks. D+ and D− signals are transmitted on a, providing data transfers for USB 2.0. Mini and micro connectors have their GND connections moved from pin #4 to pin #5, while their pin #4 serves as an ID pin for the On-The-Go host/client identification.

USB 3.0 provides two additional differential pairs (four wires, SSTx+, SSTx−, SSRx+ and SSRx−), providing data transfers at SuperSpeed, which makes it similar to or single-lane. A blue Standard-A USB connector on a Sagemcom 3864OP ADSL modem router without USB 3.0 contacts fitted. Usual USB color-coding Color Description Black or white Type-A or type-B Blue (Pantone 300C) Type-A or type-B, SuperSpeed Teal blue Type-A or type-B, SuperSpeed+ Yellow, orange or red Ports only.

High-current or USB ports and connectors are often color-coded to distinguish their different functions and USB versions. These colors are not part of the USB specification and can vary between manufacturers; for example, USB 3.0 specification mandates appropriate color-coding while it only recommends blue inserts for standard-A USB 3.0 connectors and plugs.

A USB twisted pair, where the Data+ and Data− conductors are twisted together in a double. The wires are enclosed in a further layer of shielding. The D± signals used by low, full, and high speed are carried over a (typically, unshielded) to reduce and. SuperSpeed uses separate transmit and receive, which additionally require shielding (typically, shielded twisted pair but twinax is also mentioned by the specification).

Thus, to support SuperSpeed data transmission, cables contain twice as many wires and are thus larger in diameter. The USB 1.1 standard specifies that a standard cable can have a maximum length of 3 meters with devices operating at full speed (12 Mbit/s), and a maximum length of 5 meters with devices operating at low speed (1.5 Mbit/s). USB 2.0 provides for a maximum cable length of 5 meters for devices running at high speed (480 Mbit/s). The primary reason for this limit is the maximum allowed round-trip delay of about 1.5 μs. If USB host commands are unanswered by the USB device within the allowed time, the host considers the command lost.

When adding USB device response time, delays from the maximum number of hubs added to the delays from connecting cables, the maximum acceptable delay per cable amounts to 26 ns. The USB 2.0 specification requires that cable delay be less than 5.2 ns per meter ( 192 000 km/s, which is close to the maximum achievable transmission speed for standard copper wire). The USB 3.0 standard does not directly specify a maximum cable length, requiring only that all cables meet an electrical specification: for copper cabling with 26 wires the maximum practical length is 3 meters (9.8 ft). USB power standards Specification Current Voltage Power Low-power device 100 mA 5 V 0.50 W Low-power SuperSpeed (USB 3.0) device 150 mA 5 V 0.75 W High-power device 500 mA 5 V 2.5 W High-power SuperSpeed (USB 3.0) device 900 mA 5 V 4.5 W Battery Charging (BC) 1.2 5 A 5 V 25 W Type-C 1.5 A 5 V 7.5 W 3 A 5 V 15 W Power Delivery micro-format 3 A 20 V 60 W Power Delivery standard format or Type-C 5 A 20 V 100 W. Y-shaped USB 3.0 cable; with such a cable, a device can draw power from two USB ports simultaneously USB supplies bus power across V BUS and GND at a nominal voltage 5 V ± 5%, at supply, to power USB devices. Power is sourced solely from upstream devices or hosts, and is consumed solely by downstream devices. USB provides for various voltage drops and losses in providing bus power.

As such, the voltage at the hub port is specified to be in the range 000000000♠5.00 +0.25 −0.60 V by USB 2.0, and 000000000♠5.00 +0.25 −0.55 V by USB 3.0. It is specified that devices' configuration and low-power functions must operate down to 4.40 V at the hub port by USB 2.0 and that devices' configuration, low-power, and high-power functions must operate down to 4.00 V at the device port by USB 3.0.

There are limits on the power a device may draw, stated in terms of a unit load, which is 100 mA, or 150 mA for SuperSpeed devices. There are low-power and high-power devices. Low-power devices may draw at most 1 unit load, and all devices must act as low-power devices when, starting out as, unconfigured.

High-power devices draw at least 1 unit load and at most 5 unit loads (500 mA), or 6 unit loads (900 mA) for SuperSpeed devices. A high-powered device must be configured, and may only draw as much power as specified in its configuration. I.e., the maximum power may not be available. A bus-powered hub is a high-power device providing low-power ports. It draws 1 unit load for the hub controller and 1 unit load for each of at most 4 ports. The hub may also have some non-removable functions in place of ports. A self-powered hub is a device that provides high-power ports.

Optionally, the hub controller draw power for its operation as a low-power device, but all high-power ports draw from the hub's self-power. Where devices (for example, high-speed disk drives) require more power than a high-power device can draw, they function erratically, if at all, from bus power of a single port. USB provides for these devices as being self-powered. However, such devices may come with a Y-shaped cable that has 2 USB plugs (1 for power and data, the other for only power), so as to draw power as 2 devices. Such a cable is non-standard, with the USB compliance specification stating that 'use of a 'Y' cable (a cable with two A-plugs) is prohibited on any USB peripheral', meaning that 'if a USB peripheral requires more power than allowed by the USB specification to which it is designed, then it must be self-powered.' USB Battery Charging [ ].

This USB power meter additionally provides a charge readout (in mAh) and data logging. USB Battery Charging defines a new port type, the charging port, as opposed to the standard downstream port (SDP) of the base specification. Charging ports are divided into 2 further types: the charging downstream port (CDP), which has data signals, and the dedicated charging port (DCP), which does not. Dedicated charging ports can be found on USB power adapters that convert utility power or another power source (e.g., a car's electrical system) to run attached devices and battery packs. On a host (such as a laptop computer) with both standard and charging USB ports, the charging ports should be labeled as such. The charging device identifies the type of port through non-data signalling on the D+ and D− signals immediately after attach.

A DCP simply has to place a resistance not exceeding 200 Ω across the D+ and D− signals. Per the base specification, any device attached to an SDP must initially be a low-power device, with high-power mode contingent on later USB configuration by the host.

Charging ports, however, can immediately supply up to at least 1.5 A. More current may be supplied up to the maximum current of 5 A, but the charging port may apply current limiting, or even shut down. The maximum current is determined by the over-current protection maximum current in the baseline specification. Note that it is specified only that USB connectors are tested to a contact current rating of at least 1.5 A. These bus power currents being much higher than cables were designed for, though not unsafe, cause a larger voltage between the ends of the ground signal, significantly reducing noise margins causing problems with High Speed signalling. Battery Charging 1.1 specifies that charging devices must dynamically limit bus power current draw during High Speed signalling; 1.2 simply specifies that charging devices and ports must be designed to tolerate the higher ground voltage difference in High Speed signalling.

Revision 1.2 of the specification was released in 2010. Several changes are made and limits are increased including allowing 1.5 A on charging downstream ports for unconfigured devices, allowing High Speed communication while having a current up to 1.5 A, and allowing a maximum current of 5 A. Also, support is removed for charging port detection via resistive mechanisms. Before the battery charging specification was defined, there was no standardized way for the portable device to inquire how much current was available. For example, Apple's and chargers indicate the available current by voltages on the D− and D+ lines. When D+ = D− = 2.0 V, the device may pull up to 500 mA. When D+ = 2.0 V and D− = 2.8 V, the device may pull up to 1 A of current.

When D+ = 2.8 V and D− = 2.0 V, the device may pull up to 2 A of current. Accessory charging adaptors (ACA) [ ] Portable devices having an On The Go port may want to charge and access USB peripheral at the same time, but having only a single port (both due to On The Go and space requirement) prevents this. Accessory charging adapters (ACA) are devices which allow a charging power to be injected into an On The Go connection between host and peripheral. ACAs have three ports: the OTG port for the portable device, which is required to have a Micro-A plug on a captive cable; the accessory port, which is required to have a Micro-AB or type-A receptacle; and the charging port, which is required to have a Micro-B receptacle, or type-A plug or charger on a captive cable.

The ID pin of the OTG port is not connected within plug as usual, but to the ACA itself, where signals outside the OTG floating and ground states are used for ACA detection and state signalling. The charging port does not pass data, but does use the D± signals for charging port detection. The accessory port acts as any other port. When appropriately signalled by the ACA, the portable device can charge from the bus power as if there were a charging port present; any OTG signals over bus power are instead passed to the portable device via the ID signal. Bus power is also provided to the accessory port from the charging port transparently. Power Delivery (PD) [ ] USB PD rev. 1 source profiles Profile +5 V +12 V +20 V 0 Reserved 1 2.0 A, 10 W No No 2 1.5 A, 18 W 3 3.0 A, 36 W 4 3.0 A, 60 W 5 5.0 A, 60 W 5.0 A, 100 W.

• Default start-up profile USB PD rev. 2 source power rules Source output power (W) Current, at: (A) +5 V +9 V +15 V +20 V 0.5–15 0.1–3.0 No No No 15–27 3.0 (15 W) 1.7–3.0 27–45 3.0 (27 W) 1.8–3.0 45–60 3.0 (45 W) 2.25–3.0 60–100 3.0–5.0 In July 2012, the USB Promoters Group announced the finalization of the USB Power Delivery (PD) specification, an extension that specifies using certified PD aware USB cables with standard USB Type-A and Type-B connectors to deliver increased power (more than 7.5 W) to devices with larger power demand. Devices can request higher currents and supply voltages from compliant hosts – up to 2 A at 5 V (for a power consumption of up to 10 W), and optionally up to 3 A or 5 A at either 12 V (36 W or 60 W) or 20 V (60 W or 100 W). In all cases, both host-to-device and device-to-host configurations are supported. The intent is to permit uniformly charging laptops, tablets, USB-powered disks and similarly higher-power consumer electronics, as a natural extension of existing European and Chinese mobile telephone charging standards. This may also affect the way electric power used for small devices is transmitted and used in both residential and public buildings.

The Power Delivery specification defines six fixed power profiles for the power sources. PD-aware devices implement a flexible power management scheme by interfacing with the power source through a bidirectional data channel and requesting a certain level of electrical power, variable up to 5 A and 20 V depending on supported profile.

The power configuration protocol uses a 24 MHz -coded transmission channel on the V BUS line. The USB Power Delivery revision 2.0 specification has been released as part of the USB 3.1 suite. It covers the Type-C cable and connector with four power/ground pairs and a separate configuration channel, which now hosts a low-frequency -coded data channel that reduces the possibilities for. Power Delivery protocols have been updated to facilitate Type-C features such as cable ID function, Alternate Mode negotiation, increased V BUS currents, and V CONN-powered accessories. As of USB Power Delivery Revision 2.0 Version 1.2, the six fixed power profiles for power sources have been deprecated. USB PD Power Rules replace power profiles, defining four normative voltage levels at 5V, 9V, 15V, and 20V.

Instead of six fixed profiles, power supplies may support any maximum source output power from 0.5W to 100W. Upcoming USB Power Delivery 3.0 specification defines new power rules based on supplied wattage. Programmable power supply protocol allows granular control over V BUS power in 10 mV steps to facilitate constant current or constant voltage charging. Revision 3.0 also adds extended configuration messages, fast role swap, and deprecates the BFSK protocol. As of April 2016, there are silicon controllers available from several sources (TI, Cypress) and several others. Power supplies bundled with Type-C based laptops from Apple, Google, HP, Dell, and Razer support USB PD. In addition, accessories from third party vendors including Anker,, iVoler and Innergie support USB PD 2.0 at multiple voltages.

There are several PD aware projects such as the USB-PD Sniffer that are PD aware. ASUS also make a fully Power Delivery compliant adapter card the USB 3.1 UPD PANEL Sleep-and-charge ports [ ]. A yellow USB port denoting sleep-and-charge Sleep-and-charge USB ports can be used to charge electronic devices even when the computer is switched off. Normally, when a computer is powered off the USB ports are powered down, preventing phones and other devices from charging. Sleep-and-charge USB ports remain powered even when the computer is off.

On laptops, charging devices from the USB port when it is not being powered from AC drains the laptop battery faster; most laptops have a facility to stop charging if their own battery charge level gets too low. This feature has also been implemented on some laptop docking stations allowing device charging even when no laptop is present. Sleep-and-charge USB ports may be found colored differently than regular ports, mostly red or yellow, though that is not always the case. On Dell and Toshiba laptops, the port is marked with the standard USB symbol with an added lightning bolt icon on the right side.

Dell calls this feature PowerShare, while Toshiba calls it USB Sleep-and-Charge. On and laptops, sleep-and-charge USB ports are marked with a non-standard symbol (the letters USB over a drawing of a battery); the feature is simply called Power-off USB. On some laptops such as and models, it is possible to plug a device in, close the laptop (putting it into sleep mode) and have the device continue to charge. [ ] Mobile device charger standards [ ] In China [ ]. Australian and New Zealand power socket with USB charger socket As of 14 June 2007, all new applying for a license in are required to use a USB port as a power port for battery charging.

This was the first standard to use the convention of shorting D+ and D−. OMTP/GSMA Universal Charging Solution [ ] In September 2007, the group (a forum of mobile network operators and manufacturers such as,,, and ) announced that its members had agreed on Micro-USB as the future common connector for mobile devices. The (GSMA) followed suit on 17 February 2009, and on 22 April 2009, this was further endorsed by the, with the (ITU) announcing on 22 October 2009 that it had also embraced the Universal Charging Solution as its 'energy-efficient one-charger-fits-all new mobile phone solution,' and added: 'Based on the Micro-USB interface, UCS chargers will also include a 4-star or higher efficiency rating—up to three times more energy-efficient than an unrated charger.' EU smartphone power supply standard [ ] In June 2009, many of the world's largest mobile phone manufacturers signed an -sponsored Memorandum of Understanding (MoU), agreeing to make most data-enabled mobile phones marketed in the compatible with a (common EPS).

The EU's common EPS specification (EN ) references the USB Battery Charging standard and is similar to the GSMA/OMTP and Chinese charging solutions. In January 2011, the released its version of the (EU's) common EPS standard as IEC.

Non-standard devices [ ]. Some USB devices require more power than is permitted by the specifications for a single port. This is common for external hard and, and generally for devices with. Such devices can use an, which is allowed by the standard, or use a dual-input USB cable, one input of which is used for power and data transfer, the other solely for power, which makes the device a non-standard USB device.

Some USB ports and external hubs can, in practice, supply more power to USB devices than required by the specification but a standard-compliant device may not depend on this. In addition to limiting the total average power used by the device, the USB specification limits the (i.e., that used to charge decoupling and ) when the device is first connected. Otherwise, connecting a device could cause problems with the host's internal power. USB devices are also required to automatically enter ultra low-power suspend mode when the USB host is suspended. Nevertheless, many USB host interfaces do not cut off the power supply to USB devices when they are suspended. Some non-standard USB devices use the 5 V power supply without participating in a proper USB network, which negotiates power draw with the host interface.

These are usually called. [ ] Examples include USB-powered keyboard lights, fans, mug coolers and heaters, battery chargers, miniature, and even miniature. In most cases, these items contain no digital circuitry, and thus are not standard compliant USB devices. This may cause problems with some computers, such as drawing too much current and damaging circuitry.

Prior to the Battery Charging Specification, the USB specification required that devices connect in a low-power mode (100 mA maximum) and communicate their current requirements to the host, which then permits the device to switch into high-power mode. Some devices, when plugged into charging ports, draw even more power (10 watts at 2.1 amperes) than the Battery Charging Specification allows — The is one such device. Barnes & Noble NOOK Color devices also require a special charger that runs at 1.9 amperes. PoweredUSB [ ] is a proprietary extension that adds four additional pins supplying up to 6 A at 5 V, 12 V, or 24 V. It is commonly used in systems to power peripherals such as,, and printers. Signalling (USB PHY) [ ] Signalling rate (transmission rate) [ ] Mode Abbrev Gross data rate Introduced in Low Speed LS 1.5 Mbit/s USB 1.0 Full Speed FS 12 Mbit/s USB 1.0 High Speed Also, Hi-Speed HS 480 Mbit/s USB 2.0 SuperSpeed SS 5 Gbit/s USB 3.0 SuperSpeed+ SS+ 10 Gbit/s USB 3.1 The theoretical maximum data rate in USB 2.0 is 480 Mbit/s (60 MB/s) per controller and is shared amongst all attached devices. Some chipset manufacturers overcome this bottleneck by providing multiple USB 2.0 controllers within the.

According to routine testing performed by, write operations to typical Hi-Speed hard drives can sustain rates of 25–30 MB/s, while read operations are at 30–42 MB/s; this is 70% of the total available bus bandwidth. For USB 3.0, typical write speed is 70–90 MB/s, while read speed is 90–110 MB/s.

Mask tests, also known as, are used to determine the quality of a signal in the time domain. They are defined in the referenced document as part of the electrical test description for the high-speed (HS) mode at 480 Mbit/s. According to a USB-IF chairman, 'at least 10 to 15 percent of the stated peak 60 MB/s (480 Mbit/s) of Hi-Speed USB goes to overhead—the communication protocol between the card and the peripheral. Overhead is a component of all connectivity standards'. Tables illustrating the transfer limits are shown in Chapter 5 of the USB spec. For devices like audio streams, the bandwidth is constant, and reserved exclusively for a given device. The bus bandwidth therefore only has an effect on the number of channels that can be sent at a time, not the 'speed' or of the transmission.

• Low-speed (LS) rate of 1.5 Mbit/s is defined by USB 1.0. It is very similar to full-bandwidth operation except each bit takes 8 times as long to transmit. It is intended primarily to save cost in low-bandwidth (HID) such as keyboards, mice, and joysticks. • Full-speed (FS) rate of 12 is the basic USB data rate defined by USB 1.0. All USB hubs can operate at this speed. • High-speed (HS) rate of 480 Mbit/s was introduced in 2001.

All hi-speed devices are capable of falling back to full-bandwidth operation if necessary; i.e., they are backward compatible with USB 1.1 [ ]. Connectors are identical for USB 2.0 and USB 1.x. • SuperSpeed (SS) rate of 5.0 Gbit/s. The written USB 3.0 specification was released by Intel and its partners in August 2008. The first USB 3.0 controller chips were sampled by in May 2009, and the first products using the USB 3.0 specification arrived in January 2010. USB 3.0 connectors are generally backward compatible, but include new wiring and full duplex operation. Transaction latency [ ] For low-speed ( 1.5 Mbit/s) and full-speed (12 Mbit/s) devices the shortest time for a transaction in one direction is 1 ms.

High-speed (480 Mbit/s) uses transactions within each micro frame (125 µs) where using 1-byte interrupt packet results in a minimal response time of 940 ns. 4-byte interrupt packet results in 984 ns. [ ] Electrical specification [ ] USB signals are transmitted using on a data cable with 90 ± 15%. • Low-speed (LS) and Full-speed (FS) modes use a single data pair, labelled D+ and D−, in.

Transmitted signal levels are 0.0–0.3 V for logical low, and 2.8–3.6 V for logical high level. The signal lines are not. • High-speed (HS) mode uses the same wire pair, but with different electrical conventions. Lower signal voltages of −10 to 10 mV for low and 360 to 440 mV for logical high level, and termination of 45 Ω to ground, or 90 Ω differential to match the data cable impedance.

• SuperSpeed (SS) adds two additional pairs of shielded twisted wire (and new, mostly compatible expanded connectors). These are dedicated to full-duplex SuperSpeed operation.

The half-duplex lines are still used for configuration. A USB connection is always between a host or hub at the A connector end, and a device or hub's 'upstream' port at the other end. Originally, this was a B connector, preventing erroneous loop connections, but additional upstream connectors were specified, and some cable vendors designed and sold cables that permitted erroneous connections (and potential damage to circuitry). USB interconnections are not as fool-proof or as simple as originally intended.

Signalling state [ ] The host includes 15 kΩ pull-down resistors on each data line. When no device is connected, this pulls both data lines low into the so-called single-ended zero state (SE0 in the USB documentation), and indicates a reset or disconnected connection. Line transition state [ ] To assist in technical discussion about USB PHY signalling. These are the terminology used: Signal Line transition state Description USB 1.x Low Speed (1.5 kΩ pullup on D−) USB 1.x Full Speed (1.5 kΩ pullup on D+) D+ D− D+ D− J Same as Idle line state This is present during a transmission line transition. Alternatively, it is waiting for a new packet. Low high high low K Inverse of J state This is present during a transmission line transition. High low low high SE0 Single-Ended Zero Both D+ and D− is low.

This may indicate an end of packet signal or a detached USB device. Low low low low SE1 Single-Ended One This is an illegal state and should never occur.

This is seen as an error. High high high high • The idle line state is when the device is connected to the host with a pullup on either D+ and D−, with transmitter output on both host and device is set to high impedance (hi-Z) (disconnected output).

• A USB device pulls one of the data lines high with a 1.5 kΩ resistor. This overpowers one of the pull-down resistors in the host and leaves the data lines in an idle state called J. • For USB 1.x, the choice of data line indicates what signal rates the device is capable of: • full-bandwidth devices pull D+ high, • low-bandwidth devices pull D− high. • The K state has just the opposite polarity to the J state. Line State (covering USB 1.x and 2.x) [ ] Line State/Signal Description USB 1.x Low Speed USB 1.x Full Speed USB 2.x High Speed Detached No device detected. Both line is pulled down by 15 kΩ pull-down resistors host side.

SE0 >= 2us SE0 >= 2us SE0 >= 2us Connect USB device pullups on D+ or D- will wakes the host from detached line state. This will start the USB enumeration process. This sets the Idle state.

D- is pulled up by 1.5 kΩ device side D+ is pulled up by 1.5 kΩ device side Special Chirping Ssequence Idle Host and Device Transmitter at Hi-Z. Sensing line state in case of Detached state. SE0 SE0 Sync Start of a Packet line transition pattern Line Transitions: KJKJKJKK Line Transitions: KJKJKJKK 15 KJ pairs followed by 2 K’s, for a total of 32 symbols. EOP End of Packet line transition pattern Line Transitions: SE0 + SE0 + J Line Transitions: SE0 + SE0 + J Reset Reset usb device to a known initial state SE0 >= 2.5ms SE0 >= 2.5ms Suspend Power down the device, such that it would only consume 0.5 mA from Vbus. Exits this state only after a resume or reset signal is received. To avoid this state a SOF packet (high speed) or a Keep Alive (low speed) signal is given. J >= 3ms J >= 3ms Resume (host) Host wants to wake device up K >= 20ms then EOP pattern K >= 20ms then EOP pattern Resume (device) device wants to wake up.

(Must be in idle for at least 5ms) device drives K >= 1ms host then sends a resume signal device drives K >= 1ms host then sends a resume signal Keep Alive (Low Speed) Host wants to tell low speed device to stay awake EOP pattern once every milisecond not applicable not applicable Transmission [ ] USB data is transmitted by toggling the data lines between the J state and the opposite K state. USB encodes data using the: • 0 bit is transmitted by toggling the data lines from J to K or vice versa. • 1 bit is transmitted by leaving the data lines as-is.

To ensure that there is enough signal transitions for clock recovery to occur in the, is applied to the data stream. This is via inserting extra 0 bit into the data stream after any appearance of six consecutive 1 bits (Thus ensuring that there is a 0 bit to cause a transmission state transition). Seven consecutive received 1 bits is always an error. For USB 3.0, additional data transmission encoding was included to deal with the higher speed rate that was required by the newer standard. Transmission example on a USB 1.1 Full Speed Device [ ].

Example of a Negative Acknowledge packet transmitted by USB 1.1 full-speed device when there is no more data to read. It consists of the following fields: clock synchronization byte, type of packet and end of packet.

Data packets would have more information between the type of packet and end of packet. • Synchronisation Pattern: A USB packet begins with an 8-bit synchronization sequence, 00000001₂. That is, after the initial idle state J, the data lines toggle KJKJKJKK. The final 1 bit (repeated K state) marks the end of the sync pattern and the beginning of the USB frame. For high bandwidth USB, the packet begins with a 32-bit synchronization sequence. • End Of Packet (EOP): is indicated by the transmitter driving 2 bit times of SE0 (D+ and D− both below max.) and 1 bit time of J state. After this, the transmitter ceases to drive the D+/D− lines and the aforementioned pull up resistors hold it in the J (idle) state.

Sometimes skew due to hubs can add as much as one bit time before the SE0 of the end of packet. This extra bit can also result in a 'bit stuff violation' if the six bits before it in the CRC are 1s. This bit should be ignored by receiver. • Bus Reset: A USB bus is reset using a prolonged (10 to 20 milliseconds) SE0 signal. USB 2.0 Speed Negotiation [ ] USB 2.0 devices use a special protocol during reset, called chirping, to negotiate the high bandwidth mode with the host/hub. A device that is USB 2.0 High Speed capable first connects as an Full Speed device (D+ pulled high), but upon receiving a USB RESET (both D+ and D− driven LOW by host for 10 to 20 ms) it pulls the D− line high, known as chirp K. This indicates to the host that the device is high bandwidth.

If the host/hub is also HS capable, it chirps (returns alternating J and K states on D− and D+ lines) letting the device know that the hub operates at high bandwidth. The device has to receive at least three sets of KJ chirps before it changes to high bandwidth terminations and begins high bandwidth signaling.

Because USB 3.0 uses wiring separate and additional to that used by USB 2.0 and USB 1.x, such bandwidth negotiation is not required. Clock tolerance is 480.00±0.24 Mbit/s, 12.00±0.03 Mbit/s, 1.50±0.18 Mbit/s.

Though high bandwidth devices are commonly referred to as 'USB 2.0' and advertised as 'up to 480 Mbit/s,' not all USB 2.0 devices are high bandwidth. The certifies devices and provides licenses to use special marketing logos for either 'basic bandwidth' (low and full) or high bandwidth after passing a compliance test and paying a licensing fee. All devices are tested according to the latest specification, so recently compliant low bandwidth devices are also 2.0 devices. USB 3.0 [ ] USB 3 uses tinned copper stranded AWG-28 cables with 000000000♠90 ±7 Ω impedance for its high-speed differential pairs and and sent with a voltage of 1 V nominal with a 100 mV receiver threshold; the receiver uses equalization. Clock and 300 ppm precision is used. Packet headers are protected with CRC-16, while data payload is protected with CRC-32.

Power up to 3.6 W may be used. One unit load in superspeed mode is equal to 150 mA.

Protocol layer [ ] During USB communication, data is transmitted as. Initially, all packets are sent from the host, via the root hub and possibly more hubs, to devices. Some of those packets direct a device to send some packets in reply. After the sync field, all packets are made of 8-bit bytes, transmitted. The first byte is a packet identifier (PID) byte. The PID is actually 4 bits; the byte consists of the 4-bit PID followed by its bitwise complement.

This redundancy helps detect errors. (Note also that a PID byte contains at most four consecutive 1 bits, and thus never needs bit-stuffing, even when combined with the final 1 bit in the sync byte.

A variety of USB cables for sale in Hong Kong FireWire [ ] At first, USB was considered a complement to (FireWire) technology, which was designed as a high-bandwidth serial bus that efficiently interconnects peripherals such as disk drives, audio interfaces, and video equipment. In the initial design, USB operated at a far lower data rate and used less sophisticated hardware. It was suitable for small peripherals such as keyboards and pointing devices. The most significant technical differences between FireWire and USB include: • USB networks use a topology, while IEEE 1394 networks use a topology.

• USB 1.0, 1.1 and 2.0 use a 'speak-when-spoken-to' protocol, meaning that each peripheral communicates with the host when the host specifically requests it to. USB 3.0 allows for device-initiated communications towards the host. A FireWire device can communicate with any other node at any time, subject to network conditions. • A USB network relies on a single host at the top of the tree to control the network. All communications are between the host and one peripheral. In a FireWire network, any capable node can control the network.

• USB runs with a 5 power line, while FireWire in current implementations supplies 12 V and theoretically can supply up to 30 V. • Standard USB hub ports can provide from the typical 500 mA/2.5 W of current, only 100 mA from non-hub ports. USB 3.0 and USB On-The-Go supply 1.8 A/9.0 W (for dedicated battery charging, 1.5 A/7.5 W Full bandwidth or 900 mA/4.5 W High Bandwidth), while FireWire can in theory supply up to 60 watts of power, although 10 to 20 watts is more typical. These and other differences reflect the differing design goals of the two buses: USB was designed for simplicity and low cost, while FireWire was designed for high performance, particularly in time-sensitive applications such as audio and video. Although similar in theoretical maximum transfer rate, FireWire 400 is faster than USB 2.0 Hi-Bandwidth in real-use, especially in high-bandwidth use such as external hard drives.

The newer FireWire 800 standard is twice as fast as FireWire 400 and faster than USB 2.0 Hi-Bandwidth both theoretically and practically. However, Firewire's speed advantages rely on low-level techniques such as (DMA), which in turn have created opportunities for security exploits such as the. The chipset and drivers used to implement USB and FireWire have a crucial impact on how much of the bandwidth prescribed by the specification is achieved in the real world, along with compatibility with peripherals. Ethernet [ ] The IEEE 802.3af (PoE) standard specifies a more elaborate power negotiation scheme than powered USB. It operates at 48 V and can supply more power (up to 12.95 W, PoE+ 25.5 W) over a cable up to 100 meters compared to USB 2.0, which provides 2.5 W with a maximum cable length of 5 meters. This has made PoE popular for telephones,, and other networked devices within buildings.

However, USB is cheaper than PoE provided that the distance is short, and power demand is low. Ethernet standards require electrical isolation between the networked device (computer, phone, etc.) and the network cable up to 1500 V AC or 2250 V DC for 60 seconds. USB has no such requirement as it was designed for peripherals closely associated with a host computer, and in fact it connects the peripheral and host grounds. This gives Ethernet a significant safety advantage over USB with peripherals such as cable and DSL modems connected to external wiring that can assume hazardous voltages under certain fault conditions.

Digital musical instruments are another example where USB is competitive for low-cost devices. However and the plug standard have an advantage in high-end devices that may have long cables. USB can cause problems between equipment, because it connects ground references on both transceivers.

By contrast, the MIDI plug standard and have built-in isolation to 500 V or more. ESATA/eSATAp [ ] The connector is a more robust connector, intended for connection to external hard drives and SSDs.

ESATA's transfer rate (up to 6 Gbit/s) is similar to that of USB 3.0 (up to 5 Gbit/s on current devices; 10 Gbit/s speeds via USB 3.1, announced on 31 July 2013). A device connected by eSATA appears as an ordinary SATA device, giving both full performance and full compatibility associated with internal drives. ESATA does not supply power to external devices. This is an increasing disadvantage compared to USB. Even though USB 3.0's 4.5 W is sometimes insufficient to power external hard drives, technology is advancing and external drives gradually need less power, diminishing the eSATA advantage.

(power over eSATA; aka ESATA/USB) is a connector introduced in 2009 that supplies power to attached devices using a new, backward compatible, connector. On a notebook eSATAp usually supplies only 5 V to power a 2.5-inch HDD/SSD; on a desktop workstation it can additionally supply 12 V to power larger devices including 3.5-inch HDD/SSD and 5.25-inch optical drives. ESATAp support can be added to a desktop machine in the form of a bracket connecting to motherboard SATA, power, and USB resources. ESATA, like USB, supports, although this might be limited by OS drivers and device firmware.

Thunderbolt [ ] combines and into a new serial data interface. Original Thunderbolt implementations have two channels, each with a transfer speed of 10 Gbit/s, resulting in an aggregate unidirectional bandwidth of 20 Gbit/s. Uses link aggregation to combine the two 10 Gbit/s channels into one bi-directional 20 Gbit/s channel. Is announced to use connectors. Thunderbolt 3 has one 40 Gbit/s channel. Interoperability [ ] Various are available that convert USB data signals to and from other communications standards. Related standards [ ].

The USB Implementers Forum is working on a standard based on the USB protocol. [ ] is a cable-replacement technology, and uses for data rates of up to 480 Mbit/s. USB 2.0 (HSIC) is a chip-to-chip variant of USB 2.0 that eliminates the conventional analog transceivers found in normal USB. It was adopted as a standard by the USB Implementers Forum in 2007. The HSIC uses about 50% less power and 75% less area compared to traditional USB 2.0. HSIC uses two signals at 1.2 V and has a throughput of 480 Mbit/s.

Maximum trace length for HSIC is 10 cm. It does not have low enough latency to support memory sharing between two chips. The USB 3.0 successor of HSIC is called SuperSpeed Inter-Chip (SSIC). See also [ ] References [ ]. Earlier this year, I talked about configuring Mac OS X to to the MacBook. This feature comes in handy for those users who always use a mouse and don’t want to use the built-in trackpad after connecting the mouse. In Windows operating system, a graphical option to automatically turn off the touchpad when a mouse is connected can be found under Mouse Properties in Control Panel.

In addition to that, if you’re running Windows 8.1 with the recently released August Update, you can now configure Windows 8.1 to automatically turn off the touchpad when a mouse is connected to your netbook or notebook right from PC settings. If you’re using a notebook or netbook equipped with ELAN or Synaptics touchpad, an option labelled Disable internal pointing device when a mouse is connected should appear under Mouse Properties.

Following are the steps you need to follow in order to automatically disable touchpad when a mouse is connected in Windows 10, 8/8.1 and Windows 7. Method 1 of 4 For Windows 10 Step 1:, click Devices icon and then click Mouse & touchpad. Step 2: Under Touchpad section, turn off the option labelled Leave touchpad on when a mouse is connected. Method 2 of 4 (This method should work fine on Windows 10, Windows 7, and Windows 8/8.1) Step 1: Open Control Panel by navigating to Start menu and then clicking Control Panel.

Step 2: Change the default View to Small icons. Look for the entry named Mouse and click on the same to open Mouse Properties. Step 3: Switch to the ELAN or Device Settings tab and look for an option titled Disable when external USB pointing device plug in or Disable internal pointing device when external USB pointing device is attached. Check the same option and then click Apply button.

If the above option isn’t present and you’re laptop is using Synaptics touchpad, you can try out the given below instructions to see the above mentioned option. Method 3 of 4 NOTE: We recommend you create a backup of Registry before changing default entries. Step 1: Open Registry Editor.

To do so, open Run command by simultaneously pressing Windows + R keys, type Regedit.exe in the field followed by enter key. Click on the Yes button when you see the UAC prompt. Step 2: In the Registry Editor, navigate to the following key: HKEY_LOCAL_MACHINE SOFTWARE Synaptics SynTPEnh Step 3: On the right-side, create a new DWORD value and rename it as DisableIntPDFeature. Finally, change its value to 33 (make sure that Hexdecimal is selected under Base section).

Step 4: Close the Registry Editor and reboot your PC to see Disable internal pointing device when external USB pointing device is connected option. Method 4 of 4 Disable touchpad when mouse is connected in Windows 8.1 Step 1: Open PC settings. To do so, move the mouse cursor to the upper or lower right corner of the screen to see the Charms bar, click Settings and then click Change PC settings option. Step 2: On the left-pane of PC settings, click PC and devices, and then click Mouse and touchpad. Step 3: Here, on the right-side, look for the option titled Leave touchpad on when a mouse is connected and turn off the same to automatically turn off the touchpad when you connect a mouse to your Windows 8.1 notebook or netbook. That’s it!,,..

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