A transceiver is a combination of a transmitter (Tx)/receiver (Rx) in a single package, primarily used in wireless communication devices such as wireless telephones, cellular phones, radios, etc. The name of the transceiver is irregularly used as a reference for Tx or Rx devices in cable or fiber optic systems. The main function of a transceiver is to send and receive different signals. This is most commonly used to describe components in a LAN that apply signals through network lines and detect signals flowing through the lines. For multiple LANs, it is embedded in a NIC (Network Interface Card). Some types of networks require external transceivers.