GB554491A - Telephone systems - Google Patents

Telephone systems

Info

Publication number
GB554491A
GB554491A GB14196/42A GB1419642A GB554491A GB 554491 A GB554491 A GB 554491A GB 14196/42 A GB14196/42 A GB 14196/42A GB 1419642 A GB1419642 A GB 1419642A GB 554491 A GB554491 A GB 554491A
Authority
GB
United Kingdom
Prior art keywords
condenser
relay
governed
oct
followed
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
GB14196/42A
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 GB554491A publication Critical patent/GB554491A/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
    • H04Q1/444—Signalling arrangements; Manipulation of signalling currents using alternate current with voice-band signalling frequencies
    • H04Q1/45—Signalling arrangements; Manipulation of signalling currents using alternate current with voice-band signalling frequencies using multi-frequency signalling
    • H04Q1/453—Signalling arrangements; Manipulation of signalling currents using alternate current with voice-band signalling frequencies using multi-frequency signalling in which m-out-of-n signalling frequencies are transmitted

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Monitoring And Testing Of Exchanges (AREA)
  • Telephonic Communication Services (AREA)

Abstract

554,491. Automatic exchange systems. STANDARD TELEPHONES & CABLES, Ltd. Oct. 9, 1942, No. 14196. Convention date, Oct. 15, 1941. [Class 40 (iv)] In a voice-frequency dialling system in which each digit is represented by an impulse comprising two out of a possible five frequencies, the sensitiveness of the receiver is governed by the strength of the current in the line. In the arrangement shown, the cathode circuit of the receiver tubes is normally open. On the arrival of a signal however relay 17 changes over and is followed after a delay imposed by condenser 21 by relay 18 which is followed after a further delay imposed by condenser 29 by relay 20 which completes the cathode circuits. After a further delay given by condenser 24, 19 changes over and 20 again opens the cathode circuits. The bias of the receiver tubes is governed by the potential at one end of resistance 37 through which the loop receives current and therefore depends on the length of the line.
GB14196/42A 1941-10-15 1942-10-09 Telephone systems Expired GB554491A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US554491XA 1941-10-15 1941-10-15

Publications (1)

Publication Number Publication Date
GB554491A true GB554491A (en) 1943-07-06

Family

ID=21997872

Family Applications (1)

Application Number Title Priority Date Filing Date
GB14196/42A Expired GB554491A (en) 1941-10-15 1942-10-09 Telephone systems

Country Status (1)

Country Link
GB (1) GB554491A (en)

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