Title:
インターホンシステム
Document Type and Number:
Japanese Patent JP4088435
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To additionally connect two or more interphones to an existing house information panel without the need for any modification on the house information panel. SOLUTION: The two extension interphones JB are connected to the house information panel J via a speech signal line L. Each of the extension interphones is provided with a speech use amplifier 4 and a disconnection section 5 connected to the amplifier 4. When the one extension interphone JB2 is used, the disconnection section 5 of the other extension interphone JB1 not in use is controlled to disconnect the amplifier 4 as the control. Further, in this case, a display light 11C of the extension interphone JB1 not in use is lighted. Each of the extension interphones is provided with a voltage electrode 7 for detecting a dropped voltage of the speech signal line and a hook ON/OFF detection section 3 for detecting a state of a hook switch 2 so as to discriminate the state of use of the extension interphones.
Inventors:
Ryuji Ouchi
Shigeru Kaneko
Shigeru Kaneko
Application Number:
JP2001328354A
Publication Date:
May 21, 2008
Filing Date:
October 25, 2001
Export Citation:
Assignee:
Nomi Disaster Prevention Co., Ltd.
International Classes:
H04M1/715; H04M9/00
Domestic Patent References:
| JP5036956U | ||||
| JP2283193A | ||||
| JP1143551A |