The transmission devices of carrier relay system use exclusive transmission devices and do not use IP (Internet Protocol) communications technology. But the IP communications technology has made remarkable advances recently and is used in the world. If Internet technology can adapt for the transmission device of carrier relay system, electric power company can construct the integration network for power protection and control system which includes carrier relay system. In this report, we will assume the network configuration using Internet technology for the transmission devices of a carrier relay system and show that the transmission devices using Internet technology satisfy the carrier relay specification, such as delay time and differential delay time.