Telephone line opening circuit - has common testing circuit providing line opening signal and uses additional relays to give precise time adjustments

摘要

In a circuit for opening connecting lines between transmitting devices by means of a reflex junction panel controlled via junction-forming circuits and holding circuits, the holding circuits are opened by switch controlled from a central control within the transmitting devices. All the holding circuits are connected by the switch to a common testing circuit from which a control signal which effects the opening of the connecting lines can be derived when a holding circuit has no applied voltage. The provision of additional relays and the precise adjustment of timing devices are avoided.