USB Type B Connector
USB Type B connectors, officially referred to as Standard-B connectors, are square in shape with either a slight rounding or large square protrusion on the top, depending on the USB version.
USB Type-B connectors are supported in every USB version, including USB3.0, USB2.0, and USB1.1. A second type of “B” connector, called Powered-B, also exists but only in USB 3.0.
USB 3.0 Type B connectors are often the color blue while USB 2.0 Type B and USB 1.1 Type B connectors are often black. However, this is not always the case. USB Type B connectors and cables can come in any color the manufacturer chooses.
The USB Type B connectors in USB 2.0 and USB 1.1 are identical, meaning that the USB Type B plug from one USB version will fit into the USB Type B receptacle from its own, and from the other, USB version.
USB 3.0 Type B connectors are a different shape than previous ones and so the plugs do not fit in previous receptacles. However, the new USB 3.0 Type B form factor was designed in such a way to allow previous USB Type B plugs from USB 2.0 and USB 1.1 to fit with USB 3.0 Type B receptacles.
The reason for the change is that USB 3.0 Type B connectors have nine pins, several more than the four pins found in previous USB Type B connectors, to allow for the faster USB 3.0 data transfer rate. Those pins had to go somewhere so the Type B shape had to be altered somewhat.
Important: The mere fact that a Type B connector from one USB version fits in the Type B connector from another USB version doesn’t imply anything about speed or functionality. See USB Compatibility Explained for more information on backward compatibility, maximum speeds, and more.