GB409670A - Improvements in or relating to telegraph, telephone or like exchange systems - Google Patents

Improvements in or relating to telegraph, telephone or like exchange systems

Info

Publication number
GB409670A
GB409670A GB30749/32A GB3074932A GB409670A GB 409670 A GB409670 A GB 409670A GB 30749/32 A GB30749/32 A GB 30749/32A GB 3074932 A GB3074932 A GB 3074932A GB 409670 A GB409670 A GB 409670A
Authority
GB
United Kingdom
Prior art keywords
relay
resistances
line
lines
connects
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
GB30749/32A
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
Publication of GB409670A publication Critical patent/GB409670A/en
Expired legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04Q—SELECTING
    • H04Q3/00—Selecting arrangements

Abstract

409,670. Automatic exchange systems. STANDARD TELEPHONES & CABLES, Ltd., Connaught House, Aldwych, London.- (Assignees of MatÚriel TÚlÚphonique Soc. Anon. ; 46, Quai de Boulogne, Boulogne-sur- Seine, France.) Nov. 1, 1932, No. 30749. Convention date, June 17. [Class 40 (iv).] A non-contact making relay is used as a line relay common to a number of subscribers' lines. As shown, the relay comprises a thermionic valve normally biassed so that the anode current is insufficient to operate relay L. The cut-off relay CO when de-energized connects one side of the line to ground and the other side to the junction of a pair of resistances R1, R2 connected across the grid circuit in parallel with similar resistances of other lines and in series with a negative biassing battery. When one or more lines are looped as the result of calls, the variation of bias permits L to operate. The resistances are such that line leakage does not provide bias such as would enable the valve to pass current sufficient to hold L. Slow-torelease relay H, energized by L, operates M, S, which respectively complete a loop testing circuit over T and a driving circuit for magnet FM of the finder. When the line is found, T operates and connects its left hand winding to the c wire to energize CO, double connections being prevented since two T relays cannot remain operated in parallel. H is made slow releasing since M connects battery over T to the junction of resistances R1, R2 to increase the bias and therefore release relay L.
GB30749/32A 1932-06-17 1932-11-01 Improvements in or relating to telegraph, telephone or like exchange systems Expired GB409670A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR409670X 1932-06-17

Publications (1)

Publication Number Publication Date
GB409670A true GB409670A (en) 1934-05-01

Family

ID=8897526

Family Applications (1)

Application Number Title Priority Date Filing Date
GB30749/32A Expired GB409670A (en) 1932-06-17 1932-11-01 Improvements in or relating to telegraph, telephone or like exchange systems

Country Status (1)

Country Link
GB (1) GB409670A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2419540A (en) * 1943-08-28 1947-04-29 Int Standard Electric Corp Telecommunication switching system
US2699467A (en) * 1951-03-16 1955-01-11 Automatic Elect Lab Telephone system and a relayless line circuit and circuits in cooperation therewith for extending a call

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2419540A (en) * 1943-08-28 1947-04-29 Int Standard Electric Corp Telecommunication switching system
US2699467A (en) * 1951-03-16 1955-01-11 Automatic Elect Lab Telephone system and a relayless line circuit and circuits in cooperation therewith for extending a call

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