What is USB?
USB (Universal Serial Bus) is a standard interface for connecting peripheral devices to a computer. Since its inception in 1996, it has gone through many generations and is now the most widely used connector in the world.
USB Generations and Their Speeds
- USB 1.1 — 12 Mbps, now obsolete
- USB 2.0 — 480 Mbps, still common for mice, keyboards, and charging
- USB 3.0 / USB 3.2 Gen 1 — 5 Gbps, recognizable by its blue connector
- USB 3.1 / USB 3.2 Gen 2 — 10 Gbps
- USB 3.2 Gen 2×2 — 20 Gbps, requires USB-C
- USB4 — up to 40 Gbps, compatible with Thunderbolt 3
- USB4 v2 — up to 80 Gbps (asymmetrically up to 120 Gbps for video), requires an active cable and support for PAM-3 signaling
USB Connector Types
USB comes in several physical forms. The most common are USB-A (rectangular, classic), USB-B (square, printers), Micro-USB (older phones), and USB-C (oval, modern devices). Each connector is designed for a different type of device.
Backward Compatibility
USB is designed to be backward compatible—a USB 3.0 device will work in a USB 2.0 port, albeit at a lower speed. Modern USB-C ports support older standards via adapters.
How can you tell the port’s speed?
USB 3.0 ports and faster ones are colored blue on the inside. Ports that support charging are usually marked with a lightning bolt symbol or “SS” (SuperSpeed). On laptops and monitors, look for the label right next to the port.
