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Patent Searching and Data


Title:
CALL SYSTEM, CENTRAL CONTROL DEVICE, TERMINAL STATION DEVICE AND CALL CONTROL METHOD
Document Type and Number:
WIPO Patent Application WO/2020/129431
Kind Code:
A1
Abstract:
Provided is a call system which, when allowing a terminal station device other than a terminal station device making a call to perform listening/speaking, eliminates the difficulty of speaking due to loopback voice in the terminal station device making the call. A central control device 20 transmits a voice signal received from a command station side to a plurality of terminal station devices 50, transmits a voice signal received from a terminal station side to a command station device 10 and the plurality of terminal station devices 50, and adds, to the voice signal transmitted to the plurality of terminal station devices 50, voice loopback information which indicates whether the transmission source of the voice signal is the command station side or the terminal station side. When the terminal station device 50 has received the voice signal to which the voice loopback information indicating that the transmission source is the command station side is added, and when the terminal station device 50 has received the voice signal to which the voice loopback information indicating that the transmission source is the terminal station side is added and the terminal station itself is not in a state of making a call, the terminal station device 50 reproduces and outputs the received voice signal.

Inventors:
NAKAMURA TAKASHI (JP)
NAKANO YUSUKE (JP)
AKUTAGAWA HIROYUKI (JP)
Application Number:
PCT/JP2019/043026
Publication Date:
June 25, 2020
Filing Date:
November 01, 2019
Export Citation:
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Assignee:
HITACHI INT ELECTRIC INC (JP)
International Classes:
H04M3/56; H04M3/42; H04M9/00; H04W4/42
Foreign References:
JP2003060546A2003-02-28
JP2017055252A2017-03-16
JP2013048323A2013-03-07
US20020103636A12002-08-01
JP2018148317A2018-09-20
US8570909B12013-10-29
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