GB546600A - Improvements in or relating to telephone systems - Google Patents

Improvements in or relating to telephone systems

Info

Publication number
GB546600A
GB546600A GB72441A GB72441A GB546600A GB 546600 A GB546600 A GB 546600A GB 72441 A GB72441 A GB 72441A GB 72441 A GB72441 A GB 72441A GB 546600 A GB546600 A GB 546600A
Authority
GB
United Kingdom
Prior art keywords
relay
during
line
ringing
contact
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
GB72441A
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 GB72441A priority Critical patent/GB546600A/en
Publication of GB546600A publication Critical patent/GB546600A/en
Expired legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04M—TELEPHONIC COMMUNICATION
    • H04M1/00—Substation equipment, e.g. for use by subscribers
    • H04M1/02—Constructional features of telephone sets
    • H04M1/18—Telephone sets specially adapted for use in ships, mines, or other places exposed to adverse environment

Landscapes

  • Engineering & Computer Science (AREA)
  • Signal Processing (AREA)
  • Interface Circuits In Exchanges (AREA)
  • Stand-By Power Supply Arrangements (AREA)

Abstract

546,600. Automatic exchange systems. AUTOMATIC TELEPHONE & ELECTRIC CO., Ltd., and THOMPSON, G. W. Jan. 18, 1941, No. 724. [Class 40 (iv)] A repeater for coupling a " safe " telephone system (e.g. in a fiery mine) with an automatic exchange comprises a non-linear resistance unit NLR and condenser/resistance combinations QE, YE and QF, YF as described in Specification 515,805 and an impulse relay A which is fed by a special low-voltage battery or a portion of the exchange battery and on operation energizes a release relay B and bridges a relay R across the line to the exchange apparatus to initiate the operation of a non-numerical switch in the well known way. During each digit, R is shunted by dialling relay C. Sparking at the impulse contact is quenched by a circuit QD, YO. During conversation, current is kept flowing through contact r1 via resistances YA, YB to avoid the microphonic effect of a dry contact. In the case of incoming calls, relay R in known manner, with the aid of rectifier MRA, responds to the ringing current and extends it to the safe line, the non-linear resistance limiting the voltage. When the called party replies, A responds during a non- ringing interval (in which R is back) and bridges the line 10, 11 to operate the ringing trip relay. During conversation, R remains steadily energized as with a call in the other direction.
GB72441A 1941-01-18 1941-01-18 Improvements in or relating to telephone systems Expired GB546600A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB72441A GB546600A (en) 1941-01-18 1941-01-18 Improvements in or relating to telephone systems

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB72441A GB546600A (en) 1941-01-18 1941-01-18 Improvements in or relating to telephone systems

Publications (1)

Publication Number Publication Date
GB546600A true GB546600A (en) 1942-07-21

Family

ID=9709412

Family Applications (1)

Application Number Title Priority Date Filing Date
GB72441A Expired GB546600A (en) 1941-01-18 1941-01-18 Improvements in or relating to telephone systems

Country Status (1)

Country Link
GB (1) GB546600A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1191435B (en) * 1959-12-08 1965-04-22 Siemens Ag Circuit arrangement for connecting an intrinsically safe telephone station to a non-intrinsically safe dialing center

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1191435B (en) * 1959-12-08 1965-04-22 Siemens Ag Circuit arrangement for connecting an intrinsically safe telephone station to a non-intrinsically safe dialing center

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