This schematic diagram shows an LM1893 powerline modem circuit. This circuit is used to transfer information between remote location by using the power mains. This circuit uses LM1893 that is used as a power line interface for half-duplex (bi-directional) communication of serial bit stream of virtually any coding.
Here is the schematic diagram of the circuit :
To give maximum range, impulse noise filter and a PLL-based demodulator are combined in reception. In transmission, a sinusoidal carrier is impressed and FSK modulated on most any power line via rugged on-chip driver. Besides LM1893, this circuit also uses a COPS controller and discrete components. [Circuit’s schematic diagram source: National Semiconductor’s Application Note]