USB (Universal Serial Bus) is the dominant standard for connecting small devices. It’s helpful because it allows different types of device — almost anything that you might want to connect to a computer — to use the same port.

USB logo

If you see this USB symbol on a device or its connector, you know that it will fit in a USB socket, and also that the device has been certified to comply with the USB standards (so your computer will be able to communicate with it).

There are several different kinds of USB port (they’ve changed over time), so you need to check the type of connector. The most recent is type C, but type A is still very common. You can use an adaptor to convert between them.

A major benefit of using USB is that different devices can use the same physical connections. Of course this means the size and layout of the ports (that is, the socket and the plug) are precisely defined. But USB can only work because it is a thorough specification of protocols defining how the devices at each end of the cable must communicate with each other.

The USB specification covers both the transfer of signals (data) and power. This is why low-power devices (such as keyboards or drawing tablets, for example) that are connected by USB don’t need a separate power cable. The convenience of using a single type of connector to charge mobile phones has resulted in the European Union proposing legislation to force manufacturers to adopt USB C as the standard.