A transceiver is a device which has both the transmitter and the receiver combined and they share a common circuitry. A transceiver may differ in scope from application to application. In a LAN, a NIC card may house a transceiver which applies signals onto the wire and also detects the passing signals. In radio communications, it is a two way radio equipment which can exchange information in a half-duplex mode by the use of a fast electronic switch. Some transceivers may also allow full duplex transmissions but the frequencies for sending and receiving are usually different.