GB1243863A - Improvements relating to loudspeaking telephones - Google Patents

Improvements relating to loudspeaking telephones

Info

Publication number
GB1243863A
GB1243863A GB4176369A GB4176369A GB1243863A GB 1243863 A GB1243863 A GB 1243863A GB 4176369 A GB4176369 A GB 4176369A GB 4176369 A GB4176369 A GB 4176369A GB 1243863 A GB1243863 A GB 1243863A
Authority
GB
United Kingdom
Prior art keywords
loud
terminals
line
output
speaker
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
GB4176369A
Inventor
George William Jones
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.)
Plessey Co Ltd
Original Assignee
Plessey 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 Plessey Co Ltd filed Critical Plessey Co Ltd
Priority to GB4176369A priority Critical patent/GB1243863A/en
Publication of GB1243863A publication Critical patent/GB1243863A/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
    • H04M1/60—Substation equipment, e.g. for use by subscribers including speech amplifiers
    • H04M1/6033—Substation equipment, e.g. for use by subscribers including speech amplifiers for providing handsfree use or a loudspeaker mode in telephone sets

Landscapes

  • Engineering & Computer Science (AREA)
  • Signal Processing (AREA)
  • Interconnected Communication Systems, Intercoms, And Interphones (AREA)

Abstract

1,243,863. Hybrid circuit. PLESSEY CO. Ltd. 26 May, 1970 [21 Aug., 1969], No. 41763/69. Heading H4R. A substation circuit has terminals S1, S2 for a transmitter and terminals R1, R2, for a loud-speaking receiver, terminals L1, L2, being connected to a two-wire line; a transmitter amplifier A providing an output 01 for transmission over the line and also for application to the base of a transistor T1, an equal but opposite output 02 being applied to the base of transistor T2 so that transmission produces no resultant output to load B in the common collector circuit and the transmitted signal does not reach the loud-speaker, signals received over the line being applied to T1 alone so as to drive the loud-speaker across load B.
GB4176369A 1969-08-21 1969-08-21 Improvements relating to loudspeaking telephones Expired GB1243863A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB4176369A GB1243863A (en) 1969-08-21 1969-08-21 Improvements relating to loudspeaking telephones

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB4176369A GB1243863A (en) 1969-08-21 1969-08-21 Improvements relating to loudspeaking telephones

Publications (1)

Publication Number Publication Date
GB1243863A true GB1243863A (en) 1971-08-25

Family

ID=10421269

Family Applications (1)

Application Number Title Priority Date Filing Date
GB4176369A Expired GB1243863A (en) 1969-08-21 1969-08-21 Improvements relating to loudspeaking telephones

Country Status (1)

Country Link
GB (1) GB1243863A (en)

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