GB552215A - Improvements relating to telephone systems - Google Patents

Improvements relating to telephone systems

Info

Publication number
GB552215A
GB552215A GB19742A GB19742A GB552215A GB 552215 A GB552215 A GB 552215A GB 19742 A GB19742 A GB 19742A GB 19742 A GB19742 A GB 19742A GB 552215 A GB552215 A GB 552215A
Authority
GB
United Kingdom
Prior art keywords
station
relay
party
hangs
line
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
GB19742A
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.)
Alfred Graham & Co Ltd
Original Assignee
Alfred Graham & Co Ltd
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 Alfred Graham & Co Ltd filed Critical Alfred Graham & Co Ltd
Priority to GB19742A priority Critical patent/GB552215A/en
Publication of GB552215A publication Critical patent/GB552215A/en
Expired legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04M—TELEPHONIC COMMUNICATION
    • H04M9/00—Arrangements for interconnection not involving centralised switching
    • H04M9/001—Two-way communication systems between a limited number of parties

Landscapes

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

Abstract

552,215. Direct-call systems. GRAHAM & CO., Ltd., A., and VAUGHAN, C. H. Jan. 6, 1942, No. 197. [Class 40 (iv)] In a system having two stations connected by a two-wire line in which a party calls by merely removing his receiver, false operation of the calling device of the party who hangs up first after a conversation is avoided by the provision at each station of a relay which holds until both parties have hung up. As shown, station A is provided with a battery BY while station B includes a rectifier MR which normally opposes the flow of current in the line. A calling condition is set up by reversal of the line connections at station A or by shunting of the rectifier at station B by the operation of relay HA or HB over switchhook contacts CA or CB. The calling devices CDA, CDB may be audible or visible or may take the form of a buzzer coupled to the receiver by a condenser. Each of the relays HA, HB disconnects the calling device at its own station and closes the talking circuit, and also connects up the corresponding holding relay SA or SB. When either party hangs up his relay SA or SB holds over the line until the other party also hangs up. The invention is applicable to an exchange system having several stations like B which may be interconnected at a position arranged like station A.
GB19742A 1942-01-06 1942-01-06 Improvements relating to telephone systems Expired GB552215A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB19742A GB552215A (en) 1942-01-06 1942-01-06 Improvements relating to telephone systems

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB19742A GB552215A (en) 1942-01-06 1942-01-06 Improvements relating to telephone systems

Publications (1)

Publication Number Publication Date
GB552215A true GB552215A (en) 1943-03-26

Family

ID=9700128

Family Applications (1)

Application Number Title Priority Date Filing Date
GB19742A Expired GB552215A (en) 1942-01-06 1942-01-06 Improvements relating to telephone systems

Country Status (1)

Country Link
GB (1) GB552215A (en)

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