Easily installable and highly reliable data communications over power line is a requirement to make Smart Grid more convenient and useful than fixed grid systems. Therefore RFID (Radio-Frequency IDentification) over Power Line technology was developed. Unlike conventional RFID carrying data wirelessly by antenna, radio-frequency signals for identification and payment runs through the power line in Smart Grid. The appliances embedded with IC card chips are detected and identified when their electrical plug connectors are inserted into the outlets in the electrical grid equipped with reader/writers. This system has the potential to revolutionize the usage of Power Line Communications with applications such as automatic identification, power control, and payment/ticketing through the power lines.