GB989933A - Improvements to pabx working - Google Patents

Improvements to pabx working

Info

Publication number
GB989933A
GB989933A GB4765763A GB4765763A GB989933A GB 989933 A GB989933 A GB 989933A GB 4765763 A GB4765763 A GB 4765763A GB 4765763 A GB4765763 A GB 4765763A GB 989933 A GB989933 A GB 989933A
Authority
GB
United Kingdom
Prior art keywords
relay
exchange
call
extension
dialling
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
GB4765763A
Inventor
John Arthur Barfield King
Rene Edwin Dashwood
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.)
STC PLC
Original Assignee
Standard Telephone and Cables PLC
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 Standard Telephone and Cables PLC filed Critical Standard Telephone and Cables PLC
Priority to GB4765763A priority Critical patent/GB989933A/en
Priority to BR16494064A priority patent/BR6464940D0/en
Publication of GB989933A publication Critical patent/GB989933A/en
Expired legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04Q—SELECTING
    • H04Q3/00—Selecting arrangements
    • H04Q3/58—Arrangements providing connection between main exchange and sub-exchange or satellite
    • H04Q3/62—Arrangements providing connection between main exchange and sub-exchange or satellite for connecting to private branch exchanges
    • H04Q3/625—Arrangements in the private branch exchange

Landscapes

  • Physics & Mathematics (AREA)
  • Astronomy & Astrophysics (AREA)
  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Sub-Exchange Stations And Push- Button Telephones (AREA)

Abstract

989,933. Automatic exchange systems. STANDARD TELEPHONES & CABLES Ltd. Dec. 3, 1963. No. 47657/63. Heading H4K. A PABX extension engaged in a public exchange call may make a local enquiry call while holding the exchange call but not in communication, and may by further action bring in the exchange call to form a triangular conversation. Assuming that an extension is already connected to the public exchange, momentary actuation of an earthing pushbutton operates differential relay DR which connects up relay ER. A finder LF is started and in due course connects with the calling extension, whereupon relay EB energizes, looping the exchange line but disconnecting the extension therefrom. The extension receives dialling tone, and the enquiry call is set up by dialling, the impulses being repeated by relays LS, A. Relay AS energizes upon reply and prevents further impulses reaching the local switch train. In this condition, however, the dialling of the digit 1 results in the operation of relay CB which holds in series with CA and connects up relay CE in the line circuit, thus remaking the connection to the public exchange line. If the digit 1 is dialled again, relays CB, CE are released and the previous condition is restored. The calling extension may drop the enquiry call and revert to the original exchange call by again actuating the earthing push-button to operate DR. Relay RL pulls up to release the local switch train and the relapse of EB restores the connection to the exchange line.
GB4765763A 1963-12-03 1963-12-03 Improvements to pabx working Expired GB989933A (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
GB4765763A GB989933A (en) 1963-12-03 1963-12-03 Improvements to pabx working
BR16494064A BR6464940D0 (en) 1963-12-03 1964-12-01 IMPROVEMENTS FOR THE OPERATION FOR PRIVATE AUTOMATIC CENTRAL

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB4765763A GB989933A (en) 1963-12-03 1963-12-03 Improvements to pabx working

Publications (1)

Publication Number Publication Date
GB989933A true GB989933A (en) 1965-04-22

Family

ID=10445799

Family Applications (1)

Application Number Title Priority Date Filing Date
GB4765763A Expired GB989933A (en) 1963-12-03 1963-12-03 Improvements to pabx working

Country Status (2)

Country Link
BR (1) BR6464940D0 (en)
GB (1) GB989933A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4452754A (en) * 1982-01-20 1984-06-05 The United States Of America As Represented By The United States Department Of Energy Shutdown system for a nuclear reactor

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4452754A (en) * 1982-01-20 1984-06-05 The United States Of America As Represented By The United States Department Of Energy Shutdown system for a nuclear reactor

Also Published As

Publication number Publication date
BR6464940D0 (en) 1973-09-18

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