Abstract

A local area network arrangement is taught for implementing a control system. The local area network arrangement includes a low-voltage bus composed of a cable pair, functioning as a common transmission path of the network, a plurality of connection units connecting the bus to operating devices to be controlled by the network, and a control unit common to the operating devices, connected to the bus, for controlling the operating devices. Data is transmitted in the network both from the control unit to the connection units, and from the connection units to the control unit. More particularly, the control units send to the bus a constant-frequency carrier signal whereby a number of cycles of the carrier signal form a transmission frame, in which each connection unit corresponds to a particular cycle of the frame. Also, for at least part of the cycles of the transmission frame, one half of each cycle is used for transmitting data to one specific connection unit, and the other half is used for transmitting power to all connection units.