IE43367L - Time-division switching system - Google Patents
Time-division switching systemInfo
- Publication number
- IE43367L IE43367L IE760854A IE85476A IE43367L IE 43367 L IE43367 L IE 43367L IE 760854 A IE760854 A IE 760854A IE 85476 A IE85476 A IE 85476A IE 43367 L IE43367 L IE 43367L
- Authority
- IE
- Ireland
- Prior art keywords
- bit
- word
- ram
- conference
- pcm
- Prior art date
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
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04Q—SELECTING
- H04Q11/00—Selecting arrangements for multiplex systems
- H04Q11/04—Selecting arrangements for multiplex systems for time-division multiplexing
Abstract
1529106 Automatic exchange systems NORTHERN TELECOM Ltd 2 April 1976 [23 April 1975] 13469/76 Heading H4K A pcm conference circuit is arranged to deal simultaneously with a plurality of three or more party conferences, the circuit introducing a delay of two frames. An interface and control 10 extracts from the pcm highways of the system pcm speech samples in time slots concerned with conference calls and presents the speech samples over an 8 channel serial highway to the conference circuit in isochronous (interleaved bit) form, i.e. each channel comprises 32 bits, with the first bit of each of 32 pcm words being transmitted in channel 0, and the eighth bit in channel 7 etc. The conference circuit includes two 32 word, 8 bit, RAM memories I and II, one of the memories being fed with the incoming serial bit stream during one frame, whilst information fed into the other memory during the previous frame is being processed, the units MUX, 11, 11<SP>1</SP>, enabling the 32 speech samples to be stored in the RAM's in 8 bit parallel form. The processing frame of the conference circuit is divided into eight periods, period 0 not being used. During period 1 each 8 bit word in the RAM e.g. RAM1 written during the previous frame is used to address a read only memory 14 to convert the word into a 14 bit linear PCM word, and each linear word is added to a location of an accumulator 16 corresponding to the conference to which the word relates. During period 2, the 8 bit words are again supplied to address ROM 14, but with their sign bit changed such that a 14 bit word in 2's complement form is produced at the output of ROM, 14. This word is then added to the accumulator contents value for the corresponding conference (hence effectively subtracting the word of the subscriber) and the first 8 bits of the total are written into the location of RAM I corresponding to the read 8 bit word and the remaining 6 bits are stored in a corresponding location of an additional memory RAM III. The accumulator contents remain unchanged. During period 3, the 14 bit words stored jointly in RAM I and RAM III are converted back into companded 8 bit form using compressor 18 and are fed back into the corresponding locations of RAM I. During periods 4-7 RAM III and accumulator 16 are cleared, and in the following frame the contents of RAM I are read out via interface 10 to the subscriber time slots, thereby providing each subscriber of a conference with a PCM word representing the total speech of all the other subscribers of the conference. Where the number of conferees is between 6 and 12 the ROM 14 may be enabled to produce attenuated linearly coded words. The circuit may also be switched to a public address mode by causing the ROM 14 to produce words comprising logical 1's for all except a designated speaker.
[GB1529106A]
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CA225,276A CA1027265A (en) | 1975-04-23 | 1975-04-23 | Method and apparatus for establishing a plurality of simultaneous conferences in a pcm switching system |
Publications (2)
Publication Number | Publication Date |
---|---|
IE43367L true IE43367L (en) | 1976-10-23 |
IE43367B1 IE43367B1 (en) | 1981-02-11 |
Family
ID=4102890
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
IE854/76A IE43367B1 (en) | 1975-04-23 | 1976-04-22 | Method and apparatus for establishing a plurality of simultaneous conferences in a pcm switching system |
Country Status (13)
Country | Link |
---|---|
JP (1) | JPS5916459B2 (en) |
BE (1) | BE841099A (en) |
CA (1) | CA1027265A (en) |
DE (1) | DE2617344C2 (en) |
DK (1) | DK156866C (en) |
ES (1) | ES447276A1 (en) |
FR (1) | FR2309086A1 (en) |
GB (1) | GB1529106A (en) |
IE (1) | IE43367B1 (en) |
IT (1) | IT1059227B (en) |
NL (1) | NL7604258A (en) |
NO (1) | NO761343L (en) |
SE (1) | SE420556B (en) |
Families Citing this family (16)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4112258A (en) * | 1977-10-12 | 1978-09-05 | Bell Telephone Laboratories, Incorporated | Communication system using intelligent network processor |
FR2470495B1 (en) * | 1979-11-21 | 1988-06-24 | Int Standard Electric Corp | DIGITAL TELECOMMUNICATIONS SWITCHING SYSTEM CAPABLE OF ESTABLISHING MULTILATERAL TELECONFERENCE AND SELECTIVE INFORMATION OR SIGNAL BROADCAST CONNECTIONS |
FR2475328B1 (en) * | 1979-11-21 | 1988-06-24 | Int Standard Electric Corp | DIGITAL TELECOMMUNICATIONS SWITCHING SYSTEM PROVIDED WITH CONFERENCE CONNECTION MEANS OF ONE OR MORE GROUPS OF TERMINALS |
DE3005739C2 (en) * | 1980-02-15 | 1988-11-10 | Nixdorf Computer Ag, 4790 Paderborn | Method for controlling the transmission of PCM signals between connection points of a PCM time division multiplex telecommunications network in a conference operation and circuit arrangement for carrying out the method |
US4408323A (en) | 1981-06-29 | 1983-10-04 | Bell Telephone Laboratories, Incorporated | Processor facilities for integrated packet and voice switching |
DE3147492A1 (en) * | 1981-12-01 | 1983-06-09 | Telefonbau Und Normalzeit Gmbh, 6000 Frankfurt | Circuit arrangement for setting up conference connections in telecommunications exchanges, in particular telephone exchanges, with digital through-connection using the PCM method |
US4430734A (en) * | 1981-12-14 | 1984-02-07 | Bell Telephone Laboratories, Incorporated | Demultiplexer circuit |
US4485469A (en) * | 1982-08-30 | 1984-11-27 | At&T Bell Laboratories | Time slot interchanger |
FR2533784B1 (en) * | 1982-09-28 | 1989-06-30 | Thomson Csf Mat Tel | MULTIPLE CONFERENCE DEVICE FOR MIC TIME STICKERS WITH CONNECTION NETWORK |
GB2128448B (en) * | 1982-10-08 | 1985-11-13 | Standard Telephones Cables Ltd | Telephone exchange conference circuit |
GB8301323D0 (en) * | 1983-01-18 | 1983-02-16 | Plessey Co Plc | Conference bridge |
GB2134751B (en) * | 1983-01-18 | 1986-07-30 | Plessey Co Plc | Conference bridge |
GB8324058D0 (en) * | 1983-09-08 | 1983-10-12 | Plessey Co Plc | Conference bridge circuit arrangement |
JPS60253361A (en) * | 1984-05-30 | 1985-12-14 | Fujitsu Ltd | Exchange system containing conference call function |
JPS6190564A (en) * | 1984-10-11 | 1986-05-08 | Iwatsu Electric Co Ltd | Conference calling system |
JPS61123800U (en) * | 1985-01-21 | 1986-08-04 |
Family Cites Families (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR1547633A (en) * | 1967-10-16 | 1968-11-29 | Labo Cent Telecommunicat | Circuit for adding binary numbers from non-linear signal coding |
US3551600A (en) * | 1968-02-23 | 1970-12-29 | Stromberg Carlson Corp | High capacity,high side-tone suppression,4-wire conference circuit |
FR1602502A (en) * | 1968-04-11 | 1970-12-21 | ||
US3604855A (en) * | 1970-01-02 | 1971-09-14 | Stromberg Carlson Corp | Digital conference circuit for pcm signalling system |
DE2048198C2 (en) * | 1970-09-30 | 1975-10-09 | Siemens Ag, 1000 Berlin Und 8000 Muenchen | Circuit arrangement for establishing conference connections in a PCM telecommunications, in particular telephone exchange |
-
1975
- 1975-04-23 CA CA225,276A patent/CA1027265A/en not_active Expired
-
1976
- 1976-04-02 GB GB13469/76A patent/GB1529106A/en not_active Expired
- 1976-04-20 IT IT22482/76A patent/IT1059227B/en active
- 1976-04-21 DE DE2617344A patent/DE2617344C2/en not_active Expired
- 1976-04-21 NO NO761343A patent/NO761343L/no unknown
- 1976-04-21 JP JP51044518A patent/JPS5916459B2/en not_active Expired
- 1976-04-22 IE IE854/76A patent/IE43367B1/en unknown
- 1976-04-22 NL NL7604258A patent/NL7604258A/en not_active Application Discontinuation
- 1976-04-22 DK DK181676A patent/DK156866C/en not_active IP Right Cessation
- 1976-04-23 SE SE7604727A patent/SE420556B/en not_active IP Right Cessation
- 1976-04-23 BE BE166445A patent/BE841099A/en unknown
- 1976-04-23 FR FR7612173A patent/FR2309086A1/en active Granted
- 1976-04-23 ES ES447276A patent/ES447276A1/en not_active Expired
Also Published As
Publication number | Publication date |
---|---|
NO761343L (en) | 1976-10-26 |
ES447276A1 (en) | 1977-07-01 |
JPS51135405A (en) | 1976-11-24 |
DK156866B (en) | 1989-10-09 |
GB1529106A (en) | 1978-10-18 |
IT1059227B (en) | 1982-05-31 |
BE841099A (en) | 1976-08-16 |
FR2309086A1 (en) | 1976-11-19 |
IE43367B1 (en) | 1981-02-11 |
CA1027265A (en) | 1978-02-28 |
JPS5916459B2 (en) | 1984-04-16 |
FR2309086B1 (en) | 1982-08-20 |
DK156866C (en) | 1990-02-26 |
DE2617344A1 (en) | 1976-11-04 |
NL7604258A (en) | 1976-10-26 |
SE7604727L (en) | 1976-10-24 |
DK181676A (en) | 1976-10-24 |
DE2617344C2 (en) | 1986-07-17 |
SE420556B (en) | 1981-10-12 |
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