About USB --

Universial Serial Bus(USB) is a type of connector that is used with computers and other electrical devices. It was developed by many of the corporations that control the computer industry such as Microsoft, Intel, NEC, and IBM to standardize the connection of computer peripherals such as keyboards, pointing devices, digital cameras, and disk drives. USB connectors have also become common on smartphones, PDAs and video game consoles. Not only is USB able to communicate with devices, but it is also able to act as a power supply/charger for portible devices.
The first version of USB(1.0) was released in January 1996 but few devices actually made it to market. Version 1.1 of USB was released in September 1998 and was widely accepted. The next version, USB 2.0, was released in April 2000 and was 40x faster then the previous version. USB 2.0 added many other standards over the years including mini connectors, battery charging specification, and a power management addendum. USB 3.0 was announced in November 2008 and is 10x faster then the 2.0 specification. The first USB 3.0 capable devices where released in January 2010.

What does a USB cable look like?

USB Cable Image USB Cable Image 2

Advanced Information

  • Maximum Transfer Speeds
    • USB 1.0/1.1: 12 Mbit/s
    • USB 2.0: 480 Mbit/s
    • USB 3.0: 5 Gbit/s
  • "A USB system has an asymmetric design, consisting of a host, a multitude of downstream USB ports, and multiple peripheral devices connected in a tiered-star topology. Additional USB hubs may be included in the tiers, allowing branching into a tree structure with up to five tier levels. A USB host may have 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."
  • "Though most newer computers are capable of booting off USB mass storage devices, USB is not intended to be a primary bus for a computer's internal storage: buses such as Parallel ATA (PATA or IDE), Serial ATA (SATA), or SCSI fulfill that role in PC class computers."
  • For USB 2.0 or earlier, the maximum length of a standard cable is 5 metres (16.4 ft).
  • "The USB 3.0 standard does not directly specify a maximum cable length, requiring only that all cables meet an electrical specification. For copper wire cabling, some calculations have suggested a maximum length of perhaps 3 m."