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GB780179A - Improvements in or relating to telephone instruments - Google Patents

Improvements in or relating to telephone instruments

Info

Publication number
GB780179A
GB780179A GB7553/56A GB755356A GB780179A GB 780179 A GB780179 A GB 780179A GB 7553/56 A GB7553/56 A GB 7553/56A GB 755356 A GB755356 A GB 755356A GB 780179 A GB780179 A GB 780179A
Authority
GB
United Kingdom
Prior art keywords
instrument
contacts
circuit
impulse transmitter
switch contacts
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
GB7553/56A
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.)
Telefonaktiebolaget LM Ericsson AB
Original Assignee
Telefonaktiebolaget LM Ericsson AB
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 Telefonaktiebolaget LM Ericsson AB filed Critical Telefonaktiebolaget LM Ericsson AB
Publication of GB780179A publication Critical patent/GB780179A/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
    • H04M1/738—Interface circuits for coupling substations to external telephone lines
    • H04M1/74—Interface circuits for coupling substations to external telephone lines with means for reducing interference; with means for reducing effects due to line faults
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04M—TELEPHONIC COMMUNICATION
    • H04M1/00—Substation equipment, e.g. for use by subscribers
    • H04M1/26—Devices for calling a subscriber
    • H04M1/30—Devices which can set up and transmit only one digit at a time
    • H04M1/31—Devices which can set up and transmit only one digit at a time by interrupting current to generate trains of pulses; by periodically opening and closing contacts to generate trains of pulses

Landscapes

  • Engineering & Computer Science (AREA)
  • Signal Processing (AREA)
  • Telephone Set Structure (AREA)

Abstract

780,179. Sets. TELEFONAKTIEBOLAGET L. M. ERICSSON. March 9, 1956 [March 11, 1955], No. 7553/56. Class 40 (4). An off-normal contact in the impulse transmitter of a telephone instrument is used to short-circuit the microphone and receiver and also to prevent actuation of cradle switch contacts interfering with the transmission of impulses. The invention is applied to a telephone instrument in which an impulse transmitter is mounted on the base of a handset, such as described in Specification 698,927, so as to be inaccessible when the instrument stands in its ringing position and so that it is not necessary to disconnect the impulse transmitter by means of the cradle switch contacts. In Fig. 1 the cradle switch contacts AS are operated by a pin projecting from the base of the instrument and when released from the position shown contacts AS connect up a quenching circuit for the impulsing contacts and connect one side of the speech equipment to the line. In Fig. 3 a circuit for use with a branch instrument is shown.
GB7553/56A 1955-03-11 1956-03-09 Improvements in or relating to telephone instruments Expired GB780179A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
SE780179X 1955-03-11

Publications (1)

Publication Number Publication Date
GB780179A true GB780179A (en) 1957-07-31

Family

ID=20334007

Family Applications (1)

Application Number Title Priority Date Filing Date
GB7553/56A Expired GB780179A (en) 1955-03-11 1956-03-09 Improvements in or relating to telephone instruments

Country Status (1)

Country Link
GB (1) GB780179A (en)

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