GB1402399A - Telephone exchange circuits - Google Patents

Telephone exchange circuits

Info

Publication number
GB1402399A
GB1402399A GB2123673A GB2123673A GB1402399A GB 1402399 A GB1402399 A GB 1402399A GB 2123673 A GB2123673 A GB 2123673A GB 2123673 A GB2123673 A GB 2123673A GB 1402399 A GB1402399 A GB 1402399A
Authority
GB
United Kingdom
Prior art keywords
telephone exchange
exchange circuits
relay
heading
cables
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
GB2123673A
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 GB2123673A priority Critical patent/GB1402399A/en
Priority to ZA00742302A priority patent/ZA742302B/en
Publication of GB1402399A publication Critical patent/GB1402399A/en
Expired legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04M—TELEPHONIC COMMUNICATION
    • H04M19/00—Current supply arrangements for telephone systems
    • H04M19/001—Current supply source at the exchanger providing current to substations

Landscapes

  • Engineering & Computer Science (AREA)
  • Signal Processing (AREA)
  • Telephone Function (AREA)

Abstract

1402399 Automatic exchange systems STANDARD TELEPHONES & CABLES Ltd 4 May 1973 21236/73 Heading H4K A Stone type transmission bridge includes an impulse repeating relay IR which has each of its windings connected to a line wire via the emitter collector path of a respective transistor T1, T2 connected as a constant current amplifier. The bases of the transistors are connected to respective taps on a potential divider R1, 33K R , R2, 100K R and R3, 33K R . Control functions e.g. relay contacts, may be inserted in series with IR as denoted by the dashed connection line in the battery lead.
GB2123673A 1973-05-04 1973-05-04 Telephone exchange circuits Expired GB1402399A (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
GB2123673A GB1402399A (en) 1973-05-04 1973-05-04 Telephone exchange circuits
ZA00742302A ZA742302B (en) 1973-05-04 1974-04-10 Improvements in or relating to telephone exchange circuits

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB2123673A GB1402399A (en) 1973-05-04 1973-05-04 Telephone exchange circuits

Publications (1)

Publication Number Publication Date
GB1402399A true GB1402399A (en) 1975-08-06

Family

ID=10159501

Family Applications (1)

Application Number Title Priority Date Filing Date
GB2123673A Expired GB1402399A (en) 1973-05-04 1973-05-04 Telephone exchange circuits

Country Status (2)

Country Link
GB (1) GB1402399A (en)
ZA (1) ZA742302B (en)

Also Published As

Publication number Publication date
ZA742302B (en) 1975-03-26

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Legal Events

Date Code Title Description
PS Patent sealed
746 Register noted 'licences of right' (sect. 46/1977)
PCNP Patent ceased through non-payment of renewal fee