Switching device for power supply to additional accessories for a

Abstract

In a switching device for power supply to accessories included in a telephone device, from the loop current to the telephone device, a parallel load is connected between the intercom cables for carrying the loop current, a supply current for the accessories being distributed by a current distribution switching section at the output of the parallel load, according to priority classes assigned to the respective accessories. The control device of the telephone has a highest priority, possibly in combination with a speech mode. This control device has a memory for storing the last-dialed telephone number for the purpose of repeated re-dialing. The memory contents are retained for several hours after the device is switched off the cables. The memory is powered independently of the control in an embodiment with a separate supply connection, or, where the memory is part of the control device, this device will receive its voltage supply through a capacitor, whereby the charging of the capacitor is given the next lower priority. A loudspeaker and/or hands off device can be connected to the next sequential output of the current distribution switching section, so that the capacitor reaches full charge voltage after the handset is lifted off, before the loudspeaker device is supplied with current from the loop current.