Recently, a lot of studies on the power line communication(PLC) are being done by many companies and institutes due to its own merit which can use the power line spread widely as a communication channel. But, there are many serious problems about the harsh and unpredictable characteristics, or noise, signal distortion and attenuation so it's difficult to make network with PLC. In this paper, the power line characteristics as the view point of communication channel are investigated and the technologies of PLC are proposed to control the power switch of electric machineries by using the combined method of ASK modulation , transmission, receiving pulse transformer control module and microprocessor technologies. Also experiments are carried out to ascertain performance in case of applying to electric lights control according to various distances as an example.