Connecting peripherals with USB

Hot-Swappable
Because USB connections are hot-swappable, you can attach or remove peripherals without shutting down your computer.

Different connectors
A standard USB cable features two different kinds of connectors. A USB Type A connector plugs into a host device, such as your PC. The USB Type B connector plugs into the peripheral. Having two different types of connectors helps to prevent accidental loops.

USB hub
To add more USB devices than your computer has USB connectors, you need a device called a USB hub. A hub provides additional connectors for your peripherals. Some USB devices (especially keyboards) feature built-in hubs, so you can plug yet another USB device (such as a mouse) into them.

Tiers
You can plug hubs into other hubs to provide more connections. Each new layer of hub and cable is called a tier. USB supports a maximum of 5 tiers with up to 127 attached devices. Every other hub must be externally powered in order to supply enough power to attached peripherals.

Peripherals on distance
A hub can also add additional distance between your PC and a peripheral. Each USB segment can be up to 5 metres (16.4 feet). Because USB supports up to 5 tiers, you can put peripherals a maximum of 25 metres (82 feet) from your PC.

Learn more:
USB (Universal Serial Bus)