GB508031A - Improvements in or relating to telephone systems - Google Patents

Improvements in or relating to telephone systems

Info

Publication number
GB508031A
GB508031A GB35681/37A GB3568137A GB508031A GB 508031 A GB508031 A GB 508031A GB 35681/37 A GB35681/37 A GB 35681/37A GB 3568137 A GB3568137 A GB 3568137A GB 508031 A GB508031 A GB 508031A
Authority
GB
United Kingdom
Prior art keywords
loud
speaker
microphone
switch
speech
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
GB35681/37A
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 GB35681/37A priority Critical patent/GB508031A/en
Priority to US244534A priority patent/US2224698A/en
Publication of GB508031A publication Critical patent/GB508031A/en
Expired legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04M—TELEPHONIC COMMUNICATION
    • H04M9/00—Arrangements for interconnection not involving centralised switching
    • H04M9/08—Two-way loud-speaking telephone systems with means for conditioning the signal, e.g. for suppressing echoes for one or both directions of traffic
    • 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
    • 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
    • H04M1/62—Constructional arrangements

Abstract

508,031. Sub-station circuits and sets. AUTOMATIC TELEPHONE & ELECTRIC CO., Ltd., and ROSEBY, P.N. Dec. 23, 1937, No. 35681. [Class 40 (iv)] [Also in Group XL] In a loud-speaking telephone unit the microphone and loud-speaker comprise identical units which are mounted in close proximity with their axes substantially parallel and their mouths in substantially the same plane so as to reduce acoustic coupling. The microphone 17 and loud-speaker 18 are mounted in a sloping wad 21 of sound-absorbent material held against a metal protecting grille 16 by an apertured board 20 supported by a batten 19. The set includes an on-off switch 14, an indicator lamp 15 and a receiver 12 which rests on a spring strip 13 operating a switch 24, Fig. 4, by which the loud-speaker is disconnected when the receiver is taken into use. In the operation of the switch 14 the valves V1, V2, V3 are heated by a filament-supply circuit MRA.. MRD supplying a current greater than normal until a relay XC operates and at its contact xc1 removes the short circuit from chokes L1, L2, L3 and illuminates the lamp 15. Relay X also connects the instrument to the line which terminates in an attenuation equalizer AN1 and a balancing resistance R3. Speech currents from the microphone 17 are fed through valves V1, V2 to the hybrid coil HC and small amounts of the speech-current may be fed back to the valve V3 and the loud-speaker 18 when an out-of-balance condition prevails. Speech currents from a connected station pass to the hybrid coil HC and divide between the line balancing network and the primary of the transformer T1, the currents passing to the plate circuit of the valve V2 being without effect.
GB35681/37A 1937-12-23 1937-12-23 Improvements in or relating to telephone systems Expired GB508031A (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
GB35681/37A GB508031A (en) 1937-12-23 1937-12-23 Improvements in or relating to telephone systems
US244534A US2224698A (en) 1937-12-23 1938-12-08 Telephone system

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB35681/37A GB508031A (en) 1937-12-23 1937-12-23 Improvements in or relating to telephone systems

Publications (1)

Publication Number Publication Date
GB508031A true GB508031A (en) 1939-06-23

Family

ID=10380397

Family Applications (1)

Application Number Title Priority Date Filing Date
GB35681/37A Expired GB508031A (en) 1937-12-23 1937-12-23 Improvements in or relating to telephone systems

Country Status (2)

Country Link
US (1) US2224698A (en)
GB (1) GB508031A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2542922A (en) * 1945-07-02 1951-02-20 Automatic Elect Lab Loud speaking telephine instrument

Families Citing this family (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH258989A (en) * 1942-12-04 1948-12-31 Autophon Ag Arrangement for switching the speech direction in intercom systems for noisy traffic.
US2449344A (en) * 1942-12-10 1948-09-14 Autophon Ag Device for conference calls in subscribers' devices for loud and faintly audible traffic
CH258725A (en) * 1942-12-21 1948-12-15 Autophon Ag Remote switchable self-connection telephone for noisy traffic.
GB597170A (en) * 1945-03-29 1948-01-20 Philips Nv Improvements in loud-speaking telephone arrangements
BE481181A (en) * 1947-04-29
US2506715A (en) * 1947-08-22 1950-05-09 Automatic Elect Lab Loud-speaking telephone station set with separate acoustic passages to the receiver and transmitter
GB656723A (en) * 1948-01-10 1951-08-29 Edward Shipton Improvements in or relating to telephone instruments
US2580439A (en) * 1949-09-07 1952-01-01 Bell Telephone Labor Inc Directional acoustic system
US2658947A (en) * 1949-11-25 1953-11-10 Liberman Arie Intercommunication apparatus

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2542922A (en) * 1945-07-02 1951-02-20 Automatic Elect Lab Loud speaking telephine instrument

Also Published As

Publication number Publication date
US2224698A (en) 1940-12-10

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