The power line modem (PLC Modem) is a dedicated device for transferring data over low voltage power line. Using the extensive power line cable network in a region that is distributed by a single transformer, one can use a multiple PLC Modem to form a data network among the various data terminals. Thus, a data communication network infrastructure can be formed among all the data terminals.

The unit can be used in centralized electric meter reading, remote monitoring of electrical equipment, building automation and security control, stage lighting and street lighting control applications, information displays and it can also play a role in the final leg of Internet connection in special circumstances.

The power line modem uses the power line cable as communication medium. It is convenient as it eliminates the need to lay additional cables. The modem at the transmission end modulates the signal from data terminal through RS-232 interface onto the carrier signal in the power line. At the receiving end, the modem recovers the data from the power line carrier signal by demodulation and sends the data to data terminals through RS-232 interface.