GB528023A - Improvements in or relating to telephone systems - Google Patents

Improvements in or relating to telephone systems

Info

Publication number
GB528023A
GB528023A GB1252939A GB1252939A GB528023A GB 528023 A GB528023 A GB 528023A GB 1252939 A GB1252939 A GB 1252939A GB 1252939 A GB1252939 A GB 1252939A GB 528023 A GB528023 A GB 528023A
Authority
GB
United Kingdom
Prior art keywords
line
channel
frequency
rectifiers
effected
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
GB1252939A
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.)
JOHN ERNEST THOMAS PARKER
Automatic Telephone and Electric Co Ltd
Original Assignee
JOHN ERNEST THOMAS PARKER
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 JOHN ERNEST THOMAS PARKER, Automatic Telephone and Electric Co Ltd filed Critical JOHN ERNEST THOMAS PARKER
Priority to GB1252939A priority Critical patent/GB528023A/en
Publication of GB528023A publication Critical patent/GB528023A/en
Expired legal-status Critical Current

Links

Classifications

    • 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
    • H04Q1/442—Signalling arrangements; Manipulation of signalling currents using alternate current with out-of-voice band signalling frequencies
    • H04Q1/4423—Signalling arrangements; Manipulation of signalling currents using alternate current with out-of-voice band signalling frequencies using one signalling frequency
    • 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

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Monitoring And Testing Of Transmission In General (AREA)

Abstract

528,023. Multiplex transmission. AUTOMATIC TELEPHONE & ELECTRIC CO., Ltd., PARKER, J. E. T., and McCUSKER, J. B. April 26, 1939, No. 12529. [Class 40(iv)] In a system having a carrier frequency channel and an audio-frequency channel superimposed on the same line, signalling for one channel is effected by direct current while that for the other channel is. effected by alternating curent. As shown, the channels are separated by high- and low-pass filters HPF, LPF3 and are connected to the exchange equipment over lines 10, 11 and 12, 13, the terminal apparatus for the carrier channel including a balanced modulatordemodulator MD fed by an oscillator OSC. Ringing over the audio channel is effected by low-frequency A.C. which passes directly to the line. Ringing current over the line 10, 11 operates relay R which connects positive battery through rectifiers MRL, MRM and the windings of relay M to both wires of the line 14, 15. The windings of M are normally connected to negative battery through rectifiers MRV, MRK, so that it responds to the D.C. signal and through relay C applies ringing current to the line 10, 11. The arrangement of rectifiers guards against possible operation of M by ringing current. The frequency of the oscillator OSC may be adjusted by means of a variable condenser QD, and the synchronism of the oscillators at the two ends of the line 10, 11 may be tested by plugging a telephone instrument in a jack JL, a beat frequency being heard if lack of synchronism exists.
GB1252939A 1939-04-26 1939-04-26 Improvements in or relating to telephone systems Expired GB528023A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB1252939A GB528023A (en) 1939-04-26 1939-04-26 Improvements in or relating to telephone systems

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB1252939A GB528023A (en) 1939-04-26 1939-04-26 Improvements in or relating to telephone systems

Publications (1)

Publication Number Publication Date
GB528023A true GB528023A (en) 1940-10-21

Family

ID=10006283

Family Applications (1)

Application Number Title Priority Date Filing Date
GB1252939A Expired GB528023A (en) 1939-04-26 1939-04-26 Improvements in or relating to telephone systems

Country Status (1)

Country Link
GB (1) GB528023A (en)

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