USB 1.1 Type A, USB 2.0 Type A and USB 3.0 Type A plugs and receptacles are physically compatible. USB Type A: Officially called USB Standard-A, these plugs and receptacles are rectangular and are the most commonly seen USB connectors.These are being widely adopted on smartphones and other devices. Its symmetrical design allows it to be inserted in the receptacle in either fashion, so you never have to try again (one of the biggest peeves about earlier USB plugs). This latest USB connector has finally solved the problem of which side goes up. Only USB 3.1 Type C plugs and receptacles (and thus cables) exist, but adapters for backward compatibility with USB 3.0 and 2.0 connectors are available. USB Type C: Often referred to simply as USB-C, these plugs and receptacles are rectangular with four rounded corners.The female connector on the device, computer, or extension cable is typically called the receptacle. The male connector on the cable or flash drive is typically called the plug.
