GB336946A - Improvements in circuit arrangements for conference telephones - Google Patents

Improvements in circuit arrangements for conference telephones

Info

Publication number
GB336946A
GB336946A GB19116/29A GB1911629A GB336946A GB 336946 A GB336946 A GB 336946A GB 19116/29 A GB19116/29 A GB 19116/29A GB 1911629 A GB1911629 A GB 1911629A GB 336946 A GB336946 A GB 336946A
Authority
GB
United Kingdom
Prior art keywords
substation
key
main station
relay
alarm
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
GB19116/29A
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.)
Siemens and Halske AG
Siemens AG
Original Assignee
Siemens and Halske AG
Siemens 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 Siemens and Halske AG, Siemens AG filed Critical Siemens and Halske AG
Publication of GB336946A publication Critical patent/GB336946A/en
Expired legal-status Critical Current

Links

Classifications

    • 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

Abstract

336,946. Siemens & Halske Akt.-Ges. Oct. 10, 1928, [Convention date]. Intercommunication systems.-A system comprising a main station and substations N1, N2, &c. has means by which a conference call may be established between the main station and any number of substations by connection of the latter to a common conference line, any existing connections between the called substations being released. The main station is provided with a loud-speaker 1 normally in circuit, the ordinary instruments being connected up by relay A on lifting of the switch-hook HU. A pair of wires 11, 12 lead to each substation, one for calling the substation by means of a key 15 and the other for calling the main station by means of a key 25. Alternatively a rotary switch may be employed in place of keys. When a key 15 is operated, relay B energizes in parallel with an alarm 23 and connects the receiver to the conference line. Lifting of the switch-hook H then connects up the transmitter, disconnects the alarm 23 and operates a reply signal over wire 12. If the substation is engaged in a call with another substation, the calling signal is transmitted induotively through relay B by the opening of contact b4 to alarm 30 at each substation, and the connection is released at contact b3. A contact 16 associated with each key 15 serves to operate a visible signal 18, 19 at each substation and at any other desired point.
GB19116/29A 1928-10-10 1929-06-21 Improvements in circuit arrangements for conference telephones Expired GB336946A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE336946X 1928-10-10

Publications (1)

Publication Number Publication Date
GB336946A true GB336946A (en) 1930-10-21

Family

ID=6220925

Family Applications (1)

Application Number Title Priority Date Filing Date
GB19116/29A Expired GB336946A (en) 1928-10-10 1929-06-21 Improvements in circuit arrangements for conference telephones

Country Status (2)

Country Link
FR (1) FR677584A (en)
GB (1) GB336946A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2787663A (en) * 1954-04-05 1957-04-02 Gen Dynamics Corp Conference circuit
DE1032791B (en) * 1954-07-16 1958-06-26 Western Electric Co Circuit arrangement for telephone systems with a loudspeaker device assigned to the normal subscriber station

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2787663A (en) * 1954-04-05 1957-04-02 Gen Dynamics Corp Conference circuit
DE1032791B (en) * 1954-07-16 1958-06-26 Western Electric Co Circuit arrangement for telephone systems with a loudspeaker device assigned to the normal subscriber station

Also Published As

Publication number Publication date
FR677584A (en) 1930-03-12

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