GB472993A - Improvements in or relating to alternating current signalling systems - Google Patents

Improvements in or relating to alternating current signalling systems

Info

Publication number
GB472993A
GB472993A GB988336A GB988336A GB472993A GB 472993 A GB472993 A GB 472993A GB 988336 A GB988336 A GB 988336A GB 988336 A GB988336 A GB 988336A GB 472993 A GB472993 A GB 472993A
Authority
GB
United Kingdom
Prior art keywords
relay
circuits
release
relating
alternating current
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
GB988336A
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
Priority to GB988336A priority Critical patent/GB472993A/en
Publication of GB472993A publication Critical patent/GB472993A/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

Landscapes

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

Abstract

472,993. Automatic exchange systems. STANDARD TELEPHONES & CABLES. Ltd., and BOWSHER, E. A. H. April 3, 1936, No. 9883. [Class 40 (iv)] The release of a call at a main exchange MX is signalled over a junction to a P.B.X. by changing the relative impedance of the leg circuits to which A.C. is connected in parallel at the P.B.X. so as to operate a relay AC having a winding included in each circuit, as in Fig. 1, or bridging the circuits, as in Fig. 2. Relay AC is shunted by a rectifier MR, and the A.C. is applied to the leg circuits through condensers by a relay X (not shown) upon release at the P.B.X. Since the circuits at first include the equal impedance windings of relay D, no effect is produced. When release occurs at the main exchange, one circuit is connected to relay L while the other is directly earthed, so that a difference of potential across relay AC causes its operation. If relay L is of low impedance, the operation. may be improved by a rectifier MRB in series therewith.
GB988336A 1936-04-03 1936-04-03 Improvements in or relating to alternating current signalling systems Expired GB472993A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB988336A GB472993A (en) 1936-04-03 1936-04-03 Improvements in or relating to alternating current signalling systems

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB988336A GB472993A (en) 1936-04-03 1936-04-03 Improvements in or relating to alternating current signalling systems

Publications (1)

Publication Number Publication Date
GB472993A true GB472993A (en) 1937-10-04

Family

ID=9880562

Family Applications (1)

Application Number Title Priority Date Filing Date
GB988336A Expired GB472993A (en) 1936-04-03 1936-04-03 Improvements in or relating to alternating current signalling systems

Country Status (1)

Country Link
GB (1) GB472993A (en)

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