TRUNK CIRCUIT FOR CROSSBAR SWITCHING SYSTEMS

摘要

TRUNK CIRCUIT FOR CROSSBAR SWITCHING SYSTEMS A marker-controlled crossbar switching system is disclosed having an intra-office trunk that does not require a thermal timing relay to prevent premature release of the linkage to the slower-to-hang-up-one of two parties interconnected by the trunk. Instead, the charging relay is reoperated when the first party disconnects and contacts of this relay release an auxiliary supervisory relay whose released contacts signal a "trunk idle" condition to the marker. The trunk is arranged so that if the marker reseizes the trunk for use on a new call before the second party has disconnected, the linkage to that party will be forcibly released. - i