Multimetering for telephone switching systems

Claim 2

A multimetering method adaptable to existing telecommunication switching systems in which the establishment of a connection between a calling subscriber and a called subscriber is effected at least partly via a cord circuit and where the calling subscriber is allocated a call duration counter which is arranged to be stepped forward by periodic metering signals generated by a metering signal generator, characterized in that the metering signals, which are common for all subscribers, are continuously led to an inhibiting circuit for each subscriber which in dependence on whether his call duration counter is connected to the cord circuit or not, respectively feeds the metering signals further towards his call duration counter or stops these signals.

Claim 3

A multimetering method according to claim 1 for use in connection with a telephone switching system in which multimetering of toll connections is undertaken by conventional toll multimetering equipment, characterized in that said periodic metering signals represent local multimetering and that the feeding of the call duration counter with said local multimetering signals is also inhibited if toll multimetering signals are applied, the toll multimetering signals being by-passed directly to the calling subscribers counter.

Claim 4

A multimetering method according to claim 2, in which the first local multimetering pulse is suppressed by leading the output from the inhibiting circuit to a resetable one-step shift register and that each toll multimetering pulse, when present, resets this shift register.

Claim 5

A multimetering circuit to perform the method according to claim 3, in which the winding of a relay and the emitter/collector circuits of a first and a second transistor are connected in series between the battery and earth potential, that when the called subscriber replies to a call, the calling subscriber's call duration counter is connected to the cord circuit via a contact in the cord circuit, whereby the earth (or battery) potential via the same contact is applied to the base of the second transistor making it conductive, the pulses from a clock pulse generator via a firstpulse suppressing circuit are led to the base of the first transistor making it conductive from the trailing edge of the first received clock pulse, thus operating the relay, and that the relay operating two relay contacts the first of which by-passes the first transistor and the second of which connects the clock pulse generator to the calling subscriber call counter.

Claim 6

A multimetering circuit according to claim 2, in which the toll multimetering pulses, when present, are applied via a contact in the cord circuit and that these pulses, via a threshold circuit, switch a transistor to its non-conductive state, thus inhibiting the operation of the local multimetering process, and that these pulses are also led directly to the call duration counter.

Claim 7

A multimetering circuit according to claim 5, in which the contact in the cord circuit does not close at the moment when the called subscriber replies, and a second cord circuit contact which closes just at the above described moment is used to drive the transistor to its conductive state.

Claim 8

A multimetering circuit according to claim 1, in which the potential of the connection between the call duration counter and the cord circuit is sensed substantially without power consumption and the sensed potential is used to control the inhibiting circuit.