| 摘要 |
PROBLEM TO BE SOLVED: To increase convenience in confirming recalling by amplifying the volume of a calling sound as calling notification when a recalling operation has been performed during calling from a doorphone slave unit to an interphone master unit. SOLUTION: In making a master unit speaker 202 of an interphone master unit 2a issue a calling sound showing the presence of recalling from a visitor who has performed a calling operation again by using a calling button 100 of a doorphone slave unit 1, the volume of the calling sound is secured with a sufficient volume which can be confirmed even by a resident who is absent in the neighborhood of the periphery of the interphone master unit as a volume amplified by a second amplification rate according to the action of a calling sound amplifier circuit 206 of the interphone master unit. COPYRIGHT: (C)2008,JPO&INPIT
|
