Term:USB

USB is an acronym for Universal Serial Bus, a wired interface that allows multiple various devices to be connected to a computer using a common interface.

USB (Wikipedia)

Universal Serial Bus
Certified USB.svg
The certified USB logo
Type Bus
Designer
Designed January 1996; 25 years ago (1996-01)
Produced Since May 1996
Superseded Serial port, parallel port, game port, Apple Desktop Bus, PS/2 port, and FireWire (IEEE 1394)
Length
  • 6.65 mm (type-C)
Width
  • 12 mm (type-A)
  • 8.45 mm (type-B)
  • 6.8 mm (mini/micro)
  • 8.25 mm (type-C)
Height
  • 4.5 mm (type-A)
  • 7.26 mm (type-B)
  • 10.44 mm (type-B SuperSpeed)
  • 1.8–3 mm (mini/micro)
  • 2.4 mm (type-C)
Hot pluggable Yes
External Yes
Cable
  • 4 wires plus shield
  • 9 wires plus shield (SuperSpeed)
Pins
  • 4: 1 power, 2 data, 1 ground
  • 5 (On-The-Go)
  • 9 (SuperSpeed)
  • 11 (Powered-B SuperSpeed)
  • 24 (USB-C)
Connector Unique
Signal 5 V DC
Max. voltage
  • 5.00+0.25
    −0.60
     V
  • 5.00+0.25
    −0.55
     V
    (USB 3.0)
  • 20.00 V (PD)
Max. current
  • 0.5 A (USB 2.0)
  • 0.9 A (USB 3.0)
  • 1.5 A (BC 1.2)
  • 3 A (USB-C)
  • Up to 5 A (PD)
Data signal Packet data, defined by specifications
Width 1 bit
Bitrate Depending on mode
Half-duplex (USB 1.x and USB 2.0):
1.5; 12; 480 Mbit/s
Full-duplex (USB 3.x and USB4):
5000; 10000; 20000; 40000 Mbit/s
Max. devices 127
Protocol Serial
USB.svg
Standard USB-A plug (left) and USB-B plug (right)
Pin 1   VBUS (+5 V)
Pin 2   Data−
Pin 3   Data+
Pin 4   Ground

Universal Serial Bus (USB) is an industry standard that establishes specifications for cables and connectors and protocols for connection, communication and power supply (interfacing) between computers, peripherals and other computers. A broad variety of USB hardware exists, including eleven different connectors, of which USB-C is the most recent.

Released in 1996, the USB standard is maintained by the USB Implementers Forum (USB-IF). There have been four generations of USB specifications: USB 1.x, USB 2.0, USB 3.x, and USB4.

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