A device that contains both a transmitter and receiver.
Examples: Interface devices (such as line drivers and receivers, RS-232, RS-485, RS-422, CAN, LVDS, or USB)
Wired communications ICs, such as T1/E1/J1 Transceivers (LIU and Framer) and T3/E3 Transceivers; Wireless communications such as IF and RF transceivers