GB754523A - Improvements in steady state signalling systems using alternating currents - Google Patents

Improvements in steady state signalling systems using alternating currents

Info

Publication number
GB754523A
GB754523A GB30886/54A GB3088654A GB754523A GB 754523 A GB754523 A GB 754523A GB 30886/54 A GB30886/54 A GB 30886/54A GB 3088654 A GB3088654 A GB 3088654A GB 754523 A GB754523 A GB 754523A
Authority
GB
United Kingdom
Prior art keywords
pad
speech
signal receiver
distortion
signal
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
GB30886/54A
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.)
T S SKILLMAN AND Co Pty L
Original Assignee
T S SKILLMAN AND Co Pty L
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 T S SKILLMAN AND Co Pty L filed Critical T S SKILLMAN AND Co Pty L
Publication of GB754523A publication Critical patent/GB754523A/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

Landscapes

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

Abstract

754,523. Automatic exchange systems. SKILLMAN & CO., PTY., Ltd., T. S. Oct. 26, 1954[Nov. 11, 1953], No. 30886/54. Class 40 (4). In a system in which supervisory signals are transmitted over an inter-exchange line as alternating currents outside, or cut out of, the speech band and in which intermodulation products due to distortion of speech frequencies might affect the signal receiver, arrangements are provided to reduce the speech level until the signal receiver is operated. The Figure illustrates the return half of an interexchange carrier circuit in which prior to the called party answer signal, any operator's speech necessary to the setting up of the call, and received over line L1, is attenuated by the pad P1, so that any distortion products, e.g. from the channel amplifier CA are insufficient to operate the signal receiver R. The amplification of CA is sufficient to compensate for the attenuation of the pad. The called party answer signal operates relay F which cuts out the pad P1 and connects up the signalling current from the source S. When this is received by receiver R it operates D which inserts a pad P2 in the line L2 to maintain the overall transmission equivalent constant. This signal remains on the circuit for the remainder of the conversation. If the distortion is due solely to overload on the amplifier CA then the pad P1 can immediately precede this amplifier, being switched in and out by relay D. A more sensitive signal receiver is necessary in this ease. Specifications 646,500 and 690,547 are referred to.
GB30886/54A 1953-11-11 1954-10-26 Improvements in steady state signalling systems using alternating currents Expired GB754523A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
AU754523X 1953-11-11

Publications (1)

Publication Number Publication Date
GB754523A true GB754523A (en) 1956-08-08

Family

ID=3756873

Family Applications (1)

Application Number Title Priority Date Filing Date
GB30886/54A Expired GB754523A (en) 1953-11-11 1954-10-26 Improvements in steady state signalling systems using alternating currents

Country Status (1)

Country Link
GB (1) GB754523A (en)

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