Abstract: In a system of wire-bus linked control devices with a reduced bias current requirement, all of the control devices are permanently connected to two bus bars for operational power supply, and the bus bars in turn are connected permanently with the supply poles of an operating current source. One of the control devices is equipped with a standby operating function with prompting readiness, and is continuously active in prompting readiness. Apart from its communications connection with the bus the latter control device has at least one separate signal input through which it can be prompted as well as a control output which, when the normal operating state of this control device is reached (from prompting readiness), can deliver a connect signal. Each of the other control devices has internal control means for controlling its power supply from the two bus bars and a connect control input to which a control signal for activating the internal means can be supplied.