US3941935A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Centralized debiting system for TDM telecommunication network
Assignee: Italtel SpA
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Filing: 1974-04-24
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Granted: 1976-03-02
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Expires: 1994-04-24
Abstract
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 1 , LT 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 1 or LT 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.
Inventors
- 👤 Arnaldo Vicentini
- 👤 Francesco Maschi
- 👤 Guido Arrigoni
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 08:42
CPC Classifications
H; H04; H04Q; H04Q11/00; H04Q11/04; H04M; H04M15/00
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
279 words
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.
Claim 2
Dependent Claim
279 words
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.
Claim 3
Dependent Claim
63 words
The combination defined in claim 1 wherein said counting means comprises a second memory of said group, writing means for inscribing in a corresponding phase of said second memory a numerical value progressively increasing over consecutive operating cycles, and reading means connected between said second memory and said circuit means for canceling said characteristic entry upon said numerical value reaching a predetermined limit.
Claim 4
Dependent Claim
45 words
The combination defined in claim 2 wherein said pulse-generating means comprises a third memory of said group provided with input means for entering a bit in a corresponding phase thereof during each operating cycle in which said characteristic entry is present in said one memory.
Claim 5
Dependent Claim
110 words
The combination defined in claim 2 wherein said supervisory means has a pair of alternate outputs for discriminating between toll connections charged to the account of a calling subscriber and toll connections charged to the account of a caller subscriber, said characteristic entry assuming one of two alternate forms depending upon which of said outputs is energized; said pulse-generating means comprising a pair of further memories of said group provided with input means for entering a bit in a corresponding phase of either of said further memories, depending upon the form of said characteristic entry, during each operating cycle in which said characteristic entry is present in said one memory.
Claim 6
Dependent Claim
43 words
The combination defined in claim 1 wherein said output means comprises a source of carrier wave and modulating means connected to said integrating means and to said source for varying the amplitude of said carrier wave under the control of said charge pulse.
Claim 7
Dependent Claim
25 words
The combination defined in claim 5 wherein said subscriber lines are voice channels, said carrier wave having a frequency outside the band of voice frequencies.
Claim 8
Dependent Claim
60 words
The combination defined in claim 6 wherein said subscriber lines are branches of a common voice channel terminating at said exchange, each of said branches being provided with a band-pass filter giving passage to the band of voice frequencies, said modulating means being connected to the corresponding branch at a junction between said band-pass filter and said common transmission path.
Claim 9
Dependent Claim
35 words
The combination defined in claim 7 wherein each of said branches is further provided with a filter network blocking said carrier frequency, said filter network being interposed between said common voice channel and said junction.
Claim 10
Dependent Claim
55 words
The combination defined in claim 5 wherein said modulating means comprises amplifier means provided with biasing means for cutting off said carrier wave in the absence of said charge pulse and further provided with smoothing means for rounding the edges of said charge pulse with corresponding rounding of the envelope flanks of said carrier wave.
Claim 11
Dependent Claim
117 words
The combination defined in claim 9 wherein said amplifier means comprises a plurality of cascaded transistor stages including a normally nonconductive first stage rendered conductive by said voltage pulses, a normally nonconductive second stage adapted to be driven conductive by said biasing means, a normally nonconductive third stage adapted to be driven conductive by said smoothing means, and a fourth stage constituted by a pair of matching transistors with emitters connected in parallel to the output of said third stage, with bases respectively connected to said source of carrier wave and to a point of fixed reference potential, and with collectors connected across said line through a tuned circuit resonant at the frequency of said carrier wave.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-03-02 | 1979-09-01 | 1980-03-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-03-02 | 1983-09-01 | 1984-03-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-03-02 | 1987-09-01 | 1988-03-02 | $7700.00 | Window Closed / Lapsed |