GB1455405A - Conference units - Google Patents

Conference units

Info

Publication number
GB1455405A
GB1455405A GB2374075A GB2374075A GB1455405A GB 1455405 A GB1455405 A GB 1455405A GB 2374075 A GB2374075 A GB 2374075A GB 2374075 A GB2374075 A GB 2374075A GB 1455405 A GB1455405 A GB 1455405A
Authority
GB
United Kingdom
Prior art keywords
subscribers
words
pcm
binary
adders
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
GB2374075A
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 GB2374075A priority Critical patent/GB1455405A/en
Publication of GB1455405A publication Critical patent/GB1455405A/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

Landscapes

  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Time-Division Multiplex Systems (AREA)

Abstract

1455405 Automatic exchange systems POST OFFICE 31 May 1975 23740/75 Addition to 1409610 Heading H4K The conference circuit of Specification 1,409,610 is modified by use of an adding circuit for the PCM codes comprising N-2 binary adders each capable of adding only two binary words where N is the number of conferences, N being greater than 3. To conference 5 subscribers, the linearized PCM words for each of the five subscribers are supplied in parallel format to a set of shift registers 224-226 equal in number to the number of bits in a PCM word. During a first sub time slot the sum of the words for subscribers 2-5 is performed as three stages by adders 234, 240 and 235. At the beginning of the next sub time slot the contents of the shift registers are shifted by one stage and the addition for subscribers 3-5 and 1 is performed, this process being continued until all five additions have been performed. Such an adding arrangement reduces the number of binary adders needed by 1 as compared with the adding arrangement disclosed in Specification 1,409,610 (Fig. 1, not shown).
GB2374075A 1975-05-31 1975-05-31 Conference units Expired GB1455405A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB2374075A GB1455405A (en) 1975-05-31 1975-05-31 Conference units

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB2374075A GB1455405A (en) 1975-05-31 1975-05-31 Conference units

Publications (1)

Publication Number Publication Date
GB1455405A true GB1455405A (en) 1976-11-10

Family

ID=10200528

Family Applications (1)

Application Number Title Priority Date Filing Date
GB2374075A Expired GB1455405A (en) 1975-05-31 1975-05-31 Conference units

Country Status (1)

Country Link
GB (1) GB1455405A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2493647A1 (en) * 1980-11-03 1982-05-07 Thomson Csf Mat Tel Telephone exchange conference system - uses decompression and compression circuits located respectively upstream and downstream of input and output sample stores

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2493647A1 (en) * 1980-11-03 1982-05-07 Thomson Csf Mat Tel Telephone exchange conference system - uses decompression and compression circuits located respectively upstream and downstream of input and output sample stores

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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