Power supply system

Claim 1

IN A POWER SUPPLY FOR A TELEPHONE SYSTEM, FIRST AND SECOND ALTERNATING CURRENT POWER SOURCES, SAID FIRST POWER SOURCE HAVING FIRST AND SECOND TERMINALS AND A CENTER TAP AND HAVING A POTENTIAL GREATER THAN SAID SECOND POWER SOURCE, A LOAD INCLUDING BIASED RINGERS CONNECTED TO THE CONDUCTOR OF A TELEPHONE LINE, FIRST AND SECOND PAIRS OF PARALLEL CONNECTED OPPOSITELY POLED RECTIFIERS EACH HAVING A CONDUCTION CONTROL TERMINAL, MEANS INCLUDING SAID FIRST AND SECOND PAIRS OF RECTIFIERS FOR COUPLING SAID LOAD ACROSS SAID CENTER TAP AND SAID FIRST AND SECOND TERMINALS, SWITCHING MEANS HAVING FIRST AND SECOND SWITCH POSITIONS, FIRST AND SECOND OUTPUT LEADS FROM SAID SWITCHING MEANS, SAID SWITCHING MEANS APPLYING A PREDETERMINED SIGNAL TO A SELECTED ONE OF SAID OUTPUT LEADS IN RESPONSE TO A PREDETERMINED SIGNAL FROM SAID SOURCE OF CONTROL SIGNALS, SAID FIRST AND SECOND OUTPUT LEADS CONNECTED TO SAID CONDUCTION CONTROL TERMINALS OF SAID FIRST AND SECOND RECTIFIERS IN SAID FIRST PAIR OF RECTIFIERS, RESPECTIVELY, SAID CONDUCTION CONTROL TERMINALS OF THE POLED-ALIKE DEVICES FROM SAID FIRST AND SECOND PAIRS OF RECTIFIERS CONNECTED TOGETHER, A SOURCE OF CONTROL SIGNALS REMOTE FROM SAID SWITCHING MEANS AND COUPLED THERETO BY A SIGNALING CHANNEL FOR SELECTIVELY OPERATING SAID SWITCHING MEANS TO SAID FIRST AND SECOND SWITCH POSITIONS, WHEREBY ALTERNATING POTENTIAL FROM SAID SECOND POWER SOURCE, SUPERIMPOSED ON DIRECT POTENTIAL OF FIRST AND SECOND OPPOSITE POLARITIES DERIVED FROM SAID FIRST POWER SOURCE, IS APPLIED TO SAID LOAD IN RESPONSE TO SAID SWITCHING MEANS BEING OPERATED TO SAID FIRST AND SECOND SWITCH POSITIONS, RESPECTIVELY, BY SAID CONTROL SIGNALS.