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Conference Circuit

IP.com Disclosure Number: IPCOM000088659D
Original Publication Date: 1977-Jul-01
Included in the Prior Art Database: 2005-Mar-04
Document File: 2 page(s) / 45K

Publishing Venue

IBM

Related People

Diehl, V: AUTHOR [+3]

Abstract

This circuit may be used by a number of subscribers whose telephone numbers are contained in a conference service class list stored in the central processor memory. the initiating subscriber asks the operator to call upon the other proposed conference participants. A connection is established from each such subscriber to the conference bus via a conference line circuit CLC which is switched through by the operator by means of switch S. An associated lamp L indicates the established connection. As the conference circuit is set up, an automatic short announcement circuit connected to the conference bus instructs the subscribers to wait. After setting up, the operator switches the announcement circuit off, which is the sign for starting the conference.

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Conference Circuit

This circuit may be used by a number of subscribers whose telephone numbers are contained in a conference service class list stored in the central processor memory. the initiating subscriber asks the operator to call upon the other proposed conference participants. A connection is established from each such subscriber to the conference bus via a conference line circuit CLC which is switched through by the operator by means of switch S. An associated lamp L indicates the established connection. As the conference circuit is set up, an automatic short announcement circuit connected to the conference bus instructs the subscribers to wait. After setting up, the operator switches the announcement circuit off, which is the sign for starting the conference. After having been instructed by one participant, the operator also terminates the conference by opening switches S.

The figure shows, for example, two out of 16 conference line circuits (suffixes 0, 1 ...). Each CLC includes a call detector and a connecting circuit, a 4- to 2- wire hybrid circuit, and the necessary time division gating circuitry. The hybrid circuit divides the speech path into an outgoing path g and an incoming path c. Speech samples to and from the bus are switched through by means of signal gates G.

To prevent self-regeneration and to ensure a good return loss of subscriber's own signal, the outgoing gate is switched through only during a short time interval (pulse T), whereas the...