DCU is the key equipment of low voltage powerline carrier concentrated meter reading system. It can automatically record and store all kinds of intelligent instruments with carrier communication function, network concentrator or acquisition module, and all kinds of power data of carrier communication terminal through downlink channel, and can collect electric meter data in external RS-485 connection. Its downlink channel can be low voltage power line carrier and RS-485 serial communication channel ; At the same time, it can exchange data with master station or handheld device through uplink channel. The uplink channel adopts public communication network, supports two communication modes of client and server, and adopts modularized design. The communication mode can be changed directly by replacing the communication module. In accordance with the iec International Electrotechnical Commission standards, the power information acquisition system master station and national network concentrator communication protocol, in accordance with the national network concentrator technical conditions and type specifications.