(Universal Serial Bus)

An interop standard that defines cables, connectors, and communication protocols governing the connection, communication, and power delivery between computers and peripherals.

Connectors

Type-A

Typical found on larger devices including computers and laptops. There are sub-types that indicate support for particular protocol versions.

Type-B

Square in style, mostly used on peripherals, but in declining use with the wide adoption of Type-C.

Type-C / USB-C

Commonly used on smaller devices and increasingly on compute devices given the small form factor and support for later (higher bandwidth) protocol versions

Mini

Largely retired from use in modern devices (Type-C having become the standard an mandated in many juristictions).

Micro

Largely retired from use in modern devices (Type-C having become the standard an mandated in many juristictions).

Protocol

Principal versions of the protocol are:

USB 1.1 (1998)

Maximum transfer rate of 12 Mbps. Largely obsolete.

USB 2.0 (2000)

Maximum theoretical transfer rate of 480 Mbps; real-world throughput approximately 30 MB/s. Still widely used for keyboards, mice, and storage devices.

USB 3.2 (2019)

Unified three generations:

• USB 3.2 Gen 1 (5 Gbps),
• USB 3.2 Gen 2 (10 Gbps)
• USB 3.2 Gen 2×2 (20 Gbps).