Multi-channel switching system

Claim 1

IN A MULTI-CHANNEL SWITCHING SYSTEM HAVING A PLURALITY OF CHANNEL SWITCHING RELAYS, EACH OF SAID RELAYS HAVING AT LEAST A PAIR OF NORMALLY OPEN CONTACTS, A HOLDING CIRCUIT FOR SAID RELAYS COMPRISING, A SOURCE OF POTENTIAL HAVING A COMMON OUTPUT TERMINAL, A BIAS POTENTIAL TERMINAL, AND AN ENERGIZING POTENTIAL TERMINAL, SAID SOURCE OF POTENTIAL HAVING MEANS FOR DEVELOPING A SELECTED BIAS POTENTIAL BETWEEN SAID BIAS TERMINAL AND SAID COMMON OUTPUT TERMINAL AND A SELECTED ENERGIZING POTENTIAL BETWEEN SAID ENERGIZING POTENTIAL TERMINAL AND SAID COMMON OUTPUT TERMINAL, AN IMPEDANCE CONNECTED TO SAID COMMON OUTPUT TERMINAL, INDIVIDUAL SWITCH MEANS EACH SERIALLY CONNECTED TO SAID IMPEDANCE TO FORM A COMMON JUNCTION POINT AND TO AN ASSOCIATED RELAY FOR SELECTIVE ACTUATION THEREOF, A SWITCHING AMPLIFIER HAVING CONDUCTING AND NON-CONDUCTING STATES AND PAIRS OF INPUT AND OUTPUT TERMINALS, SAID PAIRS OF INPUT TERMINALS BEING CONNECTED TO SAID BIAS TERMINAL AND TO SAID COMMON JUNCTION POINT, SAID BIAS POTENTIAL BEING EFFECTIVE TO BIAS SAID SWITCHING AMPLIFIER INTO A CONDUCTING STATE, SAID RELAYS HAVING A COMMON TERMINAL CONNECTED TO SAID ENERGIZING POTENTIAL TERMINAL, ONE OF SAID AMPLIFIER OUTPUT TERMINALS BEING CONNECTED TO SAID COMMON JUNCTION POINT, AND CIRCUIT MEANS INCLUDING SAID PAIRS OF NORMALLY OPEN CONTACTS FOR CONNECTING THE OTHER OF SAID SWITCHING AMPLIFIER OUTPUT TERMINALS TO THE JUNCTION POINT OF A SELECTED SWITCH AND ITS ASSOCIATED RELAY WHENEVER THE ASSOCIATED RELAY IS ENERGIZED AND SAID NORMALLY OPEN CONTACTS ARE CLOSED, THEREBY FORMING A FIRST INDIVIDUAL HOLDING CIRCUIT FOR THE ASSOCIATED RELAY THROUGH THE CONDUCTING SWITCHING AMPLIFIER AND THE ASSOCIATED, NOW CLOSED, NORMALLY OPEN CONTACTS, SAID SWITCHING AMPLIFIER BEING RENDERED NON-CONDUCTIVE BY THE INCREASE IN POTENTIAL DEVELOPED ACROSS SAID IMPEDANCE TO OPEN SAID FIRST HOLDING CIRCUIT, WHENEVER A SECOND SELECTED SWITCH IS CLOSED, SAID AMPLIFIER REMAINING NON-CONDUCTIVE UNTIL A SECOND INDIVIDUAL HOLDING CIRCUIT FOR SAID SECOND SELECTED SWITCH IS FORMED BY SAID CIRCUIT MEANS.