GB1409610A - Telephone exchanges - Google Patents

Telephone exchanges

Info

Publication number
GB1409610A
GB1409610A GB4916872A GB4916872A GB1409610A GB 1409610 A GB1409610 A GB 1409610A GB 4916872 A GB4916872 A GB 4916872A GB 4916872 A GB4916872 A GB 4916872A GB 1409610 A GB1409610 A GB 1409610A
Authority
GB
United Kingdom
Prior art keywords
linear
code
bit
conferee
pcm
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
GB4916872A
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Post Office
Original Assignee
Post Office
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Post Office filed Critical Post Office
Priority to GB4916872A priority Critical patent/GB1409610A/en
Publication of GB1409610A publication Critical patent/GB1409610A/en
Expired legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04M—TELEPHONIC COMMUNICATION
    • H04M3/00—Automatic or semi-automatic exchanges
    • H04M3/42—Systems providing special services or facilities to subscribers
    • H04M3/56—Arrangements for connecting several subscribers to a common circuit, i.e. affording conference facilities
    • H04M3/561—Arrangements for connecting several subscribers to a common circuit, i.e. affording conference facilities by multiplexing

Abstract

1409610 Automatic exchange systems POST OFFICE 17 Jan 1974 [25 Oct 1972] 49168/72 Heading H4K In a PCM, TDM conference circuit for conferencing more than three subscribers, a translator converts non-linear PCM code words representing the speech of each conferee into linear PCM code words. For each conferee the linear code words of the other conferees are added together and the sum is then converted into a non-linear PCM code for transmission to the conferee. In the disclosed arrangement the conference circuit can handle up to six simultaneous conferences each having up to five conferees. The circuitry is mainly concerned with the conversion of 8-bit non-linear codes into a 12-bit linear code, the binary addition of the 12-bit codes and the subsequent conversion of the summed code into an 8-bit code, and attention is directed to the Specification for a detailed description.
GB4916872A 1972-10-25 1972-10-25 Telephone exchanges Expired GB1409610A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB4916872A GB1409610A (en) 1972-10-25 1972-10-25 Telephone exchanges

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB4916872A GB1409610A (en) 1972-10-25 1972-10-25 Telephone exchanges

Publications (1)

Publication Number Publication Date
GB1409610A true GB1409610A (en) 1975-10-08

Family

ID=10451418

Family Applications (1)

Application Number Title Priority Date Filing Date
GB4916872A Expired GB1409610A (en) 1972-10-25 1972-10-25 Telephone exchanges

Country Status (1)

Country Link
GB (1) GB1409610A (en)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4225956A (en) 1978-08-28 1980-09-30 E-Systems, Inc. Multiplex conference bridge
US4229814A (en) * 1978-07-21 1980-10-21 E-Systems, Inc. Multiplex conference bridge
FR2472318A1 (en) * 1979-12-18 1981-06-26 Telecommunications Sa Telephone conference system - adds samples of selected subscriber channels and retransmits and distributes sum to subscribers as second order digital signal
EP0358028A2 (en) * 1988-09-07 1990-03-14 Siemens Aktiengesellschaft Device for a time division multiplexed digital telecommunication exchange
EP0358981A2 (en) * 1988-09-07 1990-03-21 Siemens Aktiengesellschaft Circuit for setting up conference connections in a digital time multiplexed telecommunication exchange

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4229814A (en) * 1978-07-21 1980-10-21 E-Systems, Inc. Multiplex conference bridge
US4225956A (en) 1978-08-28 1980-09-30 E-Systems, Inc. Multiplex conference bridge
FR2472318A1 (en) * 1979-12-18 1981-06-26 Telecommunications Sa Telephone conference system - adds samples of selected subscriber channels and retransmits and distributes sum to subscribers as second order digital signal
EP0358028A2 (en) * 1988-09-07 1990-03-14 Siemens Aktiengesellschaft Device for a time division multiplexed digital telecommunication exchange
EP0358981A2 (en) * 1988-09-07 1990-03-21 Siemens Aktiengesellschaft Circuit for setting up conference connections in a digital time multiplexed telecommunication exchange
EP0358028A3 (en) * 1988-09-07 1990-07-18 Siemens Aktiengesellschaft Device for a time division multiplexed digital telecommunication exchange
EP0358981A3 (en) * 1988-09-07 1990-07-18 Siemens Aktiengesellschaft Circuit for setting up conference connections in a digital time multiplexed telecommunication exchange

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Legal Events

Date Code Title Description
PS Patent sealed
746 Register noted 'licences of right' (sect. 46/1977)
732 Registration of transactions, instruments or events in the register (sect. 32/1977)
PCNP Patent ceased through non-payment of renewal fee