2. USB stands for Universal Serial Bus
Provides an expandable, fast, bi-directional, low cost,
hot pluggable Plug and Play serial hardware interface
Allows users to connect a wide variety of peripherals to
a computer and have them automatically configured
and ready to use
3. Developed and standardized by a group of leading
companies from the computer and electronics
industries in 1995
USB specifications were developed by Compaq, DEC,
IBM, Intel , Microsoft, and NEC, joined later by HP,
Lucent, and Phillips
4. USB 1.0 in January 1996
USB 1.1 in September 1998
USB 2.0 in April 2000
Important note – all versions are backwards compatible
with previous versions of USB
5. High performance
USB offers data transfer speeds at up to 480 Mbps
Expandability
Up to 127 different peripheral devices may theoretically
be connected to a single bus at one time
Bus-supplied power
USB distributes the power to all connected devices,
eliminating the need for an external power source for
low power devices (flash drives, memory cards,
Bluetooth)
6. Upgrade from USB 2.0
New communication protocols for devices
New power management features
Longer maximum cable lengths
Similar to PCI Express 2.0 technology
7. Mainly the need for faster transfer rates in devices such
as hard drives, flash card readers, DVD and HD DVD
optical drives
User applications demanding a higher performance
connection between the PC and peripherals
Need for greater energy efficiency in today’s “greener
world”
8. USB 2.0 USB 3.0
Cable is thinner Cable resembles an
Ethernet cord by
thickness
Has 4 primary
Has 8 primary
conductors conductors
Three twisted signal
Half duplex data transfer pairs for data paths and
mode one power pair
Full duplex data transfer
mode
9. A side note on the USB 3.0 cable:
Even though the USB 3.0 specifications are designed for
backwards compatibility with USB 2.0, the USB 3.0
cables are not compatible with the regular USB 2.0
connector
