A transceiver is an electronic device that can both transmit and receive signals, either wired or wireless. It is a combination of a transmitter and a receiver, hence the name. The main functionality of a transceiver is to transmit and receive different signals. In wireless communication devices, such as smartphones and cordless telephones, the transceiver is built into the mobile device. In local area networks, the transceiver is a part of the network interface card. It can both transmit signals over the network wire and detect electrical signals flowing through the wire. However, some types of networks require an external transceiver. Transceivers are used in a variety of applications, such as in baseband modems and routers for analog and digital transmission, satellite communications networks, and optical fiber cable systems. The difference between a transmitter and a transceiver is that a transmitter can only send information out, while a transceiver can both send and receive information.