GB778756A - Improvements in or relating to telephone subscribers' instruments - Google Patents

Improvements in or relating to telephone subscribers' instruments

Info

Publication number
GB778756A
GB778756A GB29656A GB29656A GB778756A GB 778756 A GB778756 A GB 778756A GB 29656 A GB29656 A GB 29656A GB 29656 A GB29656 A GB 29656A GB 778756 A GB778756 A GB 778756A
Authority
GB
United Kingdom
Prior art keywords
instruments
relating
telephone subscribers
line
resistor
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
GB29656A
Inventor
Hugh Spence Leman
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 GB29656A priority Critical patent/GB778756A/en
Publication of GB778756A publication Critical patent/GB778756A/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
    • H04M1/58—Anti-side-tone circuits

Landscapes

  • Engineering & Computer Science (AREA)
  • Signal Processing (AREA)
  • Circuits Of Receivers In General (AREA)

Abstract

778,756. Substation anti-side-tone circuits. STANDARD TELEPHONES & CABLES, Ltd. Jan. 4, 1956, No. 296/56. Addition to 775,564 Class 40 (4). The circuit of the parent Specification is modified by the replacement of inductor L and capacitor C3 by resistors R10 and R11 respectively. An additional resistor R12 in the emitter circuit gives a negative feedback effect, and a line-holding resistor R13 is connected across the line terminals. A rectifier bridge W1 maintains the correct polarity of the D.C. supply to the transistor TR. Specification 694,021 also is referred to.
GB29656A 1956-01-04 1956-01-04 Improvements in or relating to telephone subscribers' instruments Expired GB778756A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB29656A GB778756A (en) 1956-01-04 1956-01-04 Improvements in or relating to telephone subscribers' instruments

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB29656A GB778756A (en) 1956-01-04 1956-01-04 Improvements in or relating to telephone subscribers' instruments

Publications (1)

Publication Number Publication Date
GB778756A true GB778756A (en) 1957-07-10

Family

ID=9701877

Family Applications (1)

Application Number Title Priority Date Filing Date
GB29656A Expired GB778756A (en) 1956-01-04 1956-01-04 Improvements in or relating to telephone subscribers' instruments

Country Status (1)

Country Link
GB (1) GB778756A (en)

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