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GB1318858A - Telephone circuits - Google Patents

Telephone circuits

Info

Publication number
GB1318858A
GB1318858A GB4255071A GB1318858DA GB1318858A GB 1318858 A GB1318858 A GB 1318858A GB 4255071 A GB4255071 A GB 4255071A GB 1318858D A GB1318858D A GB 1318858DA GB 1318858 A GB1318858 A GB 1318858A
Authority
GB
United Kingdom
Prior art keywords
relay
contacts
circuit
capacitor
instrument
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
GB4255071A
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 GB1318858A publication Critical patent/GB1318858A/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
    • H04M19/08—Current supply arrangements for telephone systems with current supply sources at the substations
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04M—TELEPHONIC COMMUNICATION
    • H04M1/00—Substation equipment, e.g. for use by subscribers
    • H04M1/26—Devices for calling a subscriber
    • H04M1/30—Devices which can set up and transmit only one digit at a time
    • H04M1/31—Devices which can set up and transmit only one digit at a time by interrupting current to generate trains of pulses; by periodically opening and closing contacts to generate trains of pulses
    • H04M1/312—Devices which can set up and transmit only one digit at a time by interrupting current to generate trains of pulses; by periodically opening and closing contacts to generate trains of pulses pulses produced by electronic circuits

Landscapes

  • Engineering & Computer Science (AREA)
  • Signal Processing (AREA)
  • Relay Circuits (AREA)
  • Interface Circuits In Exchanges (AREA)

Abstract

1318858 Substation circuits STANDARD TELEPHONES & CABLES Ltd 13 Sept 1971 42550/71 Heading H4K A circuit for a push-button subscriber's instrument having a latching electromagnetic relay to provide loop disconnect dialling impulses includes a circuit, additional to that for driving the relay during impulsing, for closing the relay contacts when the instrument goes "off hook". In the circuit shown, capacitor C2 is charged up from the exchange battery through lines L1, L2 and when the cradle switch contacts GS1, GS2 are closed, it discharges through relay winding LR into capacitor C1, thereby closing the loop through contacts lr1 which are latched. The MOST circuitry M controls the operation of the off-normal contacts ONC and the release of relay LR to provide impulsing. If contacts lr1 inadvertently open, e.g. due to shock when the instrument is dropped, capacitor C2 will charge due to the resistance imposed by T1, T2 and relay LR will be re-operated. In a modification, the whole circuit is isolated from the lines by the cradle switch contact and a relay operating circuit is formed when this contact is closed, Fig. 2 (not shown).
GB4255071A 1971-09-13 1971-09-13 Telephone circuits Expired GB1318858A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB4255071 1971-09-13

Publications (1)

Publication Number Publication Date
GB1318858A true GB1318858A (en) 1973-05-31

Family

ID=10424913

Family Applications (1)

Application Number Title Priority Date Filing Date
GB4255071A Expired GB1318858A (en) 1971-09-13 1971-09-13 Telephone circuits

Country Status (10)

Country Link
AR (1) AR193433A1 (en)
AT (1) AT336691B (en)
AU (1) AU4603872A (en)
BE (1) BE788732A (en)
CH (1) CH556623A (en)
DE (1) DE2243994A1 (en)
FR (1) FR2153982A5 (en)
GB (1) GB1318858A (en)
IT (1) IT967355B (en)
ZA (1) ZA724726B (en)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2238225A1 (en) * 1972-08-03 1974-02-14 Itt Ind Gmbh Deutsche OPERATING WIRING OF A TELEPHONE SET
GB1394148A (en) * 1972-09-11 1975-05-14 Int Standard Electric Corp Push-button telphone subset
DE3340396C2 (en) * 1983-11-09 1987-05-07 Hagenuk GmbH, 2300 Kiel Circuit arrangement for a ringing signal generator

Also Published As

Publication number Publication date
FR2153982A5 (en) 1973-05-04
BE788732A (en) 1973-03-13
AR193433A1 (en) 1973-04-23
AU4603872A (en) 1974-03-07
ATA776172A (en) 1976-09-15
DE2243994A1 (en) 1973-03-22
CH556623A (en) 1974-11-29
IT967355B (en) 1974-02-28
ZA724726B (en) 1973-03-28
AT336691B (en) 1977-05-25

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Legal Events

Date Code Title Description
PS Patent sealed
435 Patent endorsed 'licences of right' on the date specified (sect. 35/1949)
PCNP Patent ceased through non-payment of renewal fee