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.

Main Features
◆ PLC Modem can be used for broadcasting in a one-to-many manner without the need to worry about handshaking
◆ PLC Modem can be either master or slave, depending on the pin definition of RS-232. There is no prior classification of master-slave role for the modem.
◆ A PLC Modem acting as master can be designed to work in a 3-phase manner
◆ Operating environment:
    Power : 85---275VAC, 50/60 Hz +/- 5%
    Temperature : -10 ^oC ~ +50 ^oC
    Relative humidity : ≤ 95%, non-condensation

Application Example
    The figure below shows an example in an remote automatic meter reading system. It illustrates the schematic diagram of the connection between power line modem and the data terminals using power line cables. This can be used as a reference for an actual application.

As following figure,PLC203 is 3-phase and PLC201 is single phase.