USB Type A Connector
USB Type A connector, officially called Standard-A connectors, are flat and rectangular in shape. Type A is the “original” USB connector and is the most recognizable and commonly used connector.
USB 3.0 Type A connectors are often, but not always, the color blue. USB 2.0 Type A and USB 1.1 Type A connectors are often, but not always, black.
USB Type A ports/receptacles are found on almost any modern computer-like device that can act as a USB host, including of course computers of all kinds including desktops, laptops, netbooks, and most tablets, also found on other computer-like devices like video game consoles (PlayStation, Xbox, Wii, etc.), home audio/video receivers, “smart” televisions, DVRs, streaming players (Roku, etc.), DVD and Blu-ray players, and more.
In those cases, a USB Type A plug is integrated directly into the USB device. The common flash drive is a perfect example.
The USB Type A connectors outlined in all three USB versions share basically the same form factor. This means that the USB Type A plug from any USB version will fit into the USB Type A receptacle from any other USB version, and vice versa.
USB 3.0 Type A connectors have nine pins, considerably more than the four pins that make up USB 2.0 and USB 1.1 Type A connectors. These additional pins are used to enable the faster data transfer rate found in USB 3.0 but they are placed in the connectors in a way that does not prevent them from physically working with Type A connectors from the previous USB standards.
Important: Just because the Type A connector from one USB version fits in the Type A connector from another USB version does not mean that the connected devices will work at the highest speed, or even at all. See USB Compatibility Explained for more information on backward compatibility, maximum speeds, and more.