Communication switching system and outlet testing circuit arrangement therefor

Claim 1

IN A COMMUNICATION SWITCHING SYSTEM, A PLURALITY OF SWITCHING NETWORKS EACH HAVING A PLURALITY OF OUTLETS; A PLURALITY OF TERMINATING UNITS EACH HAVING AN INLET CONNECTED IN MULTIPLE VIA TRUNKS TO AN OUTLET OF EACH OF A PLURALITY OF SAID SWITCHING NETWORKS, AN IDLE TEST IMPEDANCE DEVICE IN EACH TERMINATING UNIT CONNECTED TO AN IDLE TEST CONDUCTOR OF EACH TRUNK WHICH IS CONNECTED TO THE INLET OF THE TERMINATING UNIT; THERE BEING ASSOCIATED WITH THE SWITCHING NETWORKS A PLURALITY OF MARKERS, EACH OF WHICH INCLUDES AN OUTLET SELECTOR HAVING A PLURALITY OF TEST TERMINALS, A PLURALITY OF TRANSISTOR GATES INDIVIDUALLY CONNECTED THERETO, AND A BISTABLE TRANSISTOR TRIGGER CIRCUIT HAVING A COMMON CONNECTION TO ALL OF SAID GATES OF THE OUTLET SELECTOR; MEANS FOR CONNECTING THE TEST TERMINALS OF AN OUTLET SELECTOR TO THE IDLE TEST LEADS OF A GROUP OF OUTLEST OF A SWITCHING NETWORK, AND MEANS FOR THEN SUPPLYING ENABLING PULSES TO ONE AT A TIME OF THE GATES OF THE OUTLET SELECTOR; MEANS IN EAHC SAID TRIGGER CIRCUIT RESPONSIVE TO THE ENABLING OF A GATE CONNECTED THERETO AND TO THE IDLE TEST DEVICE OF A TERMINATING UNIT WHICH IS IDLE FOR INITIATING THE SWITCHING TO AN "ON" STATE OF THE TRIGGER CIRCUIT, THEREBY DRAWING CURRENT THROUGH SAID IDLE TEST DEVICE, AND FOR PERMITTING ONLY ONE TRIGGER CIRCUIT CONNECTED VIA AN ENABLED GATE TO THE LAST SAID IDLE TEST DEVICE TO FULLY SWITCH TO THE "ON" STATE, CAUSING ANY OTHER SUCH TRIGGER CIRCUIT SIMULTANEOUSLY CONNECTED TO THE SAME DEVICE TO REVERT OR REMAIN IN THE "OFF" STATE.