- A type connectors, rectangular in shape.
They are usually used for devices with low bandwidth (keyboard, mouse, webcam).
- Connectors of type B, square-shaped.
They are used mainly for devices such as external hard drives, high-speed.
The maximum length allowed by the standard is 3 m unshielded cable so generally for a \Low\ (= 1.5 Mb/s) USB device and 5 m for shielded Cable in the case of a Full USB (12 Mb/s =).
The USB cable is composed of two different forms :
Upstream a plug called a connector USB type, connected to the PC and stream type B or mini B :
In 2008, USB 3.0 introduced the gear (SuperSpeed 625 MB/s) mode. But this new mode using a coding of data type 8B / 10B, the actual transfer speed is only 500 MB/s.
The USB 3 delivers an electric output of 4.5 watts.
New devices have connections to 6 contacts instead of 4, the backward compatibility of the sockets and cables with previous versions is guaranteed.
On the other hand, backward compatibility is impossible, cable USB 3.0 type B are not compatible with USB 1.1/2.05 catches, in this case using adapters.
In early 2010, the USB 3 is introduced into consumer products. Corresponding sockets are marked with a blue color.
Appear as red USB Sockets, indicating an available electrical power top, and suitable for quick loading of small devices even when the computer is turned off.
(if you set it up in the BIOS or EFI USB)