US 3,941,935 AGranted

Centralized debiting system for TDM telecommunication network

AssigneeSocieta Italiana Telecomunicazioni Siemens S.p.A.

InventorsArnaldo Vicentini, Francesco Maschi, Guido Arrigoni

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Abstract

A telephone exchange of the time-division-multiplex type is provided with several synchronized circulating memories whose operating cycle is divided into, say, 100 phases corresponding to respective time slots of a communication frame whereby a multiplicity of conversations can be initiated and carried on simultaneously between calling and responding subscribers. These memories include a caller memory I, a responder memory N, a monitoring memory LP, a counting memory LK, and two ancillary memories LT.sub.1, LT.sub.2 respectively associated with the caller and the responder. Monitoring memory LP, registering the progress of a call in a corresponding phase thereof, defines up to 10 different states in the establishment of a connection; in the event of a toll call, state No. 10 is followed by either state No. 11 or state No. 12, depending on whether the charge is to be debited to the calling or the called party, wherever a supervisory unit emits a rate pulse. In either case, the counting memory LK registers a series of clock pulses in successive cycles which measure the length of a charge pulse to be stored in ancillary memory LT.sub.1 or LT.sub.2 in the form of a bit recurring over a predetermined number of cycles. The charge pulse read out from the ancillary memory during the corresponding time slot of a frame is integrated and rounded in a harmonics suppressor before being used to modulate the amplitude of a high-frequency carrier delivered to the respective subscriber line for stepping a pulse counter connected thereto.

Claims10

Dependent claims

In a time-division-multiplex telecommunication system including an exchange serving a multiplicity of subscriber lines, in combination:

central-office equipment at said exchange for establishing a connection between a calling subscriber and a called subscriber, at least some connections so established being toll calls to be debited to participating subscribers, said equipment including a group of synchronously circulating memories for the temporary storage of data relating to the progress of a multiplicity of connections concurrently established in respective time slots of a recurrent communication frame, each of said memories having an operating cycle coextensive with said frame and subdivided into a multiplicity of phases corresponding to the time slots of said frame;
supervisory means operative upon the stablishment of a toll call in one of said time slots for generating a succession of rate pulses indicative of the number of toll units to be charged to the account of a subscriber participating in said toll call;
circuit means connecting said supervisory means to one memory of said group for registering a characteristic entry in a phase thereof, assigned to said toll call, in response to a rate signal;
counting means controlled by said circuit means for preserving said characteristic entry in said assigned phase for a predetermined number of operating cycles;
pulse-generating means controlled by said one memory for emitting a voltage pulse upon each occurrence of each characteristic entry in successive operating cycles;
integrating means connected to said pulse-generating means for converting a train of said voltage pulses into a single charge pulse;
and
output means connected to said integrating means for delivering said charge pulse to the line of the participating subscriber to be debited for the toll call.

5 more elements

Dependencies are inferred from the claim text.