GB602333A - Improvements in telephone systems adapted for using loud speakers and normal receivers - Google Patents

Improvements in telephone systems adapted for using loud speakers and normal receivers

Info

Publication number
GB602333A
GB602333A GB5808/45A GB580845A GB602333A GB 602333 A GB602333 A GB 602333A GB 5808/45 A GB5808/45 A GB 5808/45A GB 580845 A GB580845 A GB 580845A GB 602333 A GB602333 A GB 602333A
Authority
GB
United Kingdom
Prior art keywords
relay
over
loud
speaker
amplifier
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
GB5808/45A
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.)
Autophon AG
Original Assignee
Autophon AG
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 Autophon AG filed Critical Autophon AG
Publication of GB602333A publication Critical patent/GB602333A/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
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04M—TELEPHONIC COMMUNICATION
    • H04M3/00—Automatic or semi-automatic exchanges
    • H04M3/42—Systems providing special services or facilities to subscribers
    • H04M3/56—Arrangements for connecting several subscribers to a common circuit, i.e. affording conference facilities

Landscapes

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

Abstract

602,333. Substation equipment. AUTOPHON AKT.-GES. March 8, 1945, No. 5808. Convention date, Dec. 10, 1942. [Class 40 (iv)] A substation provided with a loud-speaker which is also used as a microphone comprises in addition a normal telephone receiver whose hook-switch besides providing for changing over from loud-speaker to normal telephone reception connects up the loud-speaker as a microphone. The arrangement finds particular use in enabling subscribers to break in during conference calls. In the calling sub-station, relay E, which energizes the amplifier V, is initially operated over the off-normal contacts k of the dial by - ve D.C., received over the phantom from the exchange, to which it subsequently locks. In the called substation, E operates to an initial A.C. pulse from the exchange and locks to subsequent D.C. Relay U is normally operated by the above D.C. to connect the amplifier V as a receiver. Removal of receiver T from the switch hook operates TK to disconnect U, whereupon the amplifier is connected as a transmitter. The calling subscriber may also break in by operating the dial so that its off-normal contacts k then shortcircuit U. The conference is called by dialling a special digit which on setting a connector, Fig. 2 (not shown), operates a relay over the third wire to common and busy all conference subscribers and a further relay is operated over the same circuit to transmit the A.C. pulse followed by the - ve D.C. to the sub-stations.
GB5808/45A 1942-12-10 1945-03-08 Improvements in telephone systems adapted for using loud speakers and normal receivers Expired GB602333A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CH602333X 1942-12-10

Publications (1)

Publication Number Publication Date
GB602333A true GB602333A (en) 1948-05-25

Family

ID=4522824

Family Applications (1)

Application Number Title Priority Date Filing Date
GB5808/45A Expired GB602333A (en) 1942-12-10 1945-03-08 Improvements in telephone systems adapted for using loud speakers and normal receivers

Country Status (2)

Country Link
CH (1) CH256355A (en)
GB (1) GB602333A (en)

Also Published As

Publication number Publication date
CH256355A (en) 1948-08-15

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