The second type of interface that falls under the standard USB interface is the USB Type-B, which is typically used for larger peripherals such as printers and scanners. Considering these kind of devices requires a higher power supply, they constantly equipped with a extra power supply port. As for the inner structure, USB Type-B also has four pins, and in fact, the electrical characteristics of USB-Type B are identical to those of USB-Type A. USB Type-B is designed in such a shape to prevent users from using the interface incorrectly. The design is so shaped, presumably to prevent short-circuiting due to incorrect use of the interface by product users.
Interestingly, a very awkward situation occurred with the USB Type-B update to the USB 3.0 era. In the introduction of Type-A interface, we found that the space within the initial generation of Type-A interface is very abundant, so the extra 5 pins directly “squeeze” into the original designed interface without any changes of the size or the appearance of the USB Type-A face. On the other hand, the USB-Type B, perhaps the original designer did not even consider that it will be updated, the narrow internal space for the extra five pins have nowhere to put. So the USB 3.0 version of Type-B was given a “crown” to accommodate the five pins.