GB567164A - Improvements in telephone or like systems - Google Patents

Improvements in telephone or like systems

Info

Publication number
GB567164A
GB567164A GB1217943A GB1217943A GB567164A GB 567164 A GB567164 A GB 567164A GB 1217943 A GB1217943 A GB 1217943A GB 1217943 A GB1217943 A GB 1217943A GB 567164 A GB567164 A GB 567164A
Authority
GB
United Kingdom
Prior art keywords
rectifiers
relay
biassed
mre
mrf
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
GB1217943A
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.)
Automatic Telephone and Electric Co Ltd
Original Assignee
Automatic Telephone and Electric 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 Automatic Telephone and Electric Co Ltd filed Critical Automatic Telephone and Electric Co Ltd
Priority to GB1217943A priority Critical patent/GB567164A/en
Publication of GB567164A publication Critical patent/GB567164A/en
Expired legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J1/00—Frequency-division multiplex systems
    • H04J1/02—Details
    • H04J1/14—Arrangements providing for calling or supervisory signals
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04Q—SELECTING
    • H04Q1/00—Details of selecting apparatus or arrangements
    • H04Q1/18—Electrical details
    • H04Q1/30—Signalling arrangements; Manipulation of signalling currents
    • H04Q1/44—Signalling arrangements; Manipulation of signalling currents using alternate current
    • H04Q1/444—Signalling arrangements; Manipulation of signalling currents using alternate current with voice-band signalling frequencies
    • H04Q1/446—Signalling arrangements; Manipulation of signalling currents using alternate current with voice-band signalling frequencies using one signalling frequency
    • H04Q1/4465—Signalling arrangements; Manipulation of signalling currents using alternate current with voice-band signalling frequencies using one signalling frequency the same frequency being used for all signalling information, e.g. A.C. nr.9 system

Landscapes

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

Abstract

567,164. Exchange systems. AUTOMATIC TELEPHONE & ELECTRIC CO., Ltd., GILLINGS, C., and RHODES, C. July 27, 1943, No. 12179. [Class 40 (iv)] The talking circuit at the incoming end of a junction over which voice frequency signalling is employed includes a variable attenuator of the biassed rectifier type which, on the receipt of signals, is biassed to produce maximum attenuation and thus to block the circuit beyond the signal receiver. As shown, the attenuator is connected between transformers T1, T2 and is normally biassed so that the series rectifiers MRC, MRD are conductive while the shunt rectifiers MRA, MRB are non-conductive. On the operation of relay CA (not shown) in response to a signal, this condition is reversed and in effect a low resistance shunt is placed across the line. The transformer T2 has a centre-tapped tertiary winding which is shunted by resistances YE, YF and rectifiers MRE, MRF in order to provide a suitable line termination in both directions, this termination being eliminated on the reply of the called party by the operation of relay IR (not shown) which alters the bias to render the rectifiers MRE, MRF non-conducting. The loss introduced by the line termination is such that conversation is not seriously impaired on non-metered calls when relay IR is inoperative. A condenser QA provides a low impedance path for voicefrequency currents which might affect the distribution of the bias potentials.. Specification 560,794 is referred to.
GB1217943A 1943-07-27 1943-07-27 Improvements in telephone or like systems Expired GB567164A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB1217943A GB567164A (en) 1943-07-27 1943-07-27 Improvements in telephone or like systems

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB1217943A GB567164A (en) 1943-07-27 1943-07-27 Improvements in telephone or like systems

Publications (1)

Publication Number Publication Date
GB567164A true GB567164A (en) 1945-01-31

Family

ID=9999780

Family Applications (1)

Application Number Title Priority Date Filing Date
GB1217943A Expired GB567164A (en) 1943-07-27 1943-07-27 Improvements in telephone or like systems

Country Status (1)

Country Link
GB (1) GB567164A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2170906A1 (en) * 1972-02-08 1973-09-21 Lignes Telegraph Telephon

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2170906A1 (en) * 1972-02-08 1973-09-21 Lignes Telegraph Telephon

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