Automatic charge metering of telephone calls

Claim 1

A CIRCUIT ARRANGEMENT FOR AUTOMATIC CHARGE METERING IN TELEPHONE SYSTEMS COMPRISING MAIN AND SUB-EXCHANGES, IDENTIFYING DEVICES RESPECTIVELY COOPERATIVELY ASSOCIATED INDIVIDUALLY WITH INDIVIDUAL EXCHANGES, AND SUBEXCHANGE TRANSMISSIONS ARRANGED AT THE MAIN EXCHANGE AND CARRYING THE TRAFFIC FROM AND TO THE INDIVIDUAL SUBEXCHANGES, AN IDENTIFYING DEVICE DISPOSED AT THE MAIN EXCHANGE AT WHICH PRINTED RECORDS ARE MADE OF CHARGES FOR CALLS, FOR DETERMINING SAID TRANSMISSIONS AS WELL AS SUBSCRIBER STATIONS OF THE MAIN EXCHANGE, MEANS RESPONSIVE TO IDENTIFICATION OF SUB-EXCHANGE TRAMSMISSION FOR EFFECTING THE DETERMINATION AND TRANSMISSION OF THE CALLING SUBSCRIBER STATION APPLICABLE WITHIN THE RESPECTIVE SUBEXCHANGE, MARKING POINTS ALLOCATED RESPECTIVELY TO THE INDIVIDUAL SUB-EXCHANGE TRANSMISSIONS WITHIN THE IDENTIFICATION DEVICE, WHICH IS ALLOCATED TO THE MAIN EXCHANGE, SAID MARKING POINTS BEING CONNECTED WITH A FURTHER CHARACTERIZING DEVICE FOR SO EFFECTING THE OPERATIONAL CONTROL OF THE IDENTIFICATION DEVICE THAT THERE IS ASCERTAINED ONLY THE NUMBER OF DIGITS OF THE NUMBER CHARACTERIZING THE RESPECTIVE SUB-EXCHANGE WHICH HAS BEEN DETERMINED BY THE CHARACTERIZING DEVICE.