A remote communication system of a network includes a main controller and a plurality of control units, wherein each control unit is serially connected to the main controller and the control unit at next stage through a transmission terminal and a transmitter. Each control unit receives the data sent from the main controller and identifies the received data as one of a first, a second and a third packet. If it is the first packet and the main controller attempts to read data from each control unit, a switch in the control unit is turned on and a response data is transmitted to the main controller. If it is the second packet and a connection index is equal to a target unit address, then data is written to a corresponding single control unit. If it is the third packet and a target unit address is zero, data is written to all control units.