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 PLCfiledCriticalStandard Telephone and Cables PLC
Priority to GB29656ApriorityCriticalpatent/GB778756A/en
Publication of GB778756ApublicationCriticalpatent/GB778756A/en
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.
GB29656A1956-01-041956-01-04Improvements in or relating to telephone subscribers' instruments
ExpiredGB778756A
(en)