COLLECTIVE HOUSING INTERCOM SYSTEM AND SYSTEM EXPANSION DEVICE

Japanese Patent JP2015053740

A

PROBLEM TO BE SOLVED: To provide a collective housing intercom system allowing simultaneous communication using main lines of plural systems while reducing a loss on main lines of the systems.SOLUTION: The collective housing intercom system having a communication channel includes: sub-main lines of plural systems in which one or plural dwelling unit terminals which are branched therefrom and connected thereto; and a main line in which the sub-main lines of the plural systems are branched therefrom and connected thereto via plural branching devices. Each of the plural branching devices includes: a pair of main line connection sections which are inserted in series along the main line; a sub-main line connection section to which the sub main lines to the system expansion device are connected; and a branching circuit for branching a signal flowing a pair of main line connections to the sub-main line connection.

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MIZUTA TOMOAKI
MAEJIMA MASAYUKI
FURUYA TOMOHIDE
UMEDA NAOKI
MAEDA MITSURU
HYOZU HARUHIKO

JP2014253319A

March 19, 2015

December 15, 2014

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PANASONIC CORP

H04M9/06

JP2007235220A	2007-09-13
JP2010178072A	2010-08-12
JPH0715724A	1995-01-17
JP2007166109A	2007-06-28

WO2012081707A1

2012-06-21

Yoshikiyo Nishikawa
Takeshi Sakaguchi
Hidetoshi Kitade
Haruki Nakaishi

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