Two-wire television interphone system with power saving

A two-wire television interphone system has a line voltage discriminator 12, in a master device MA which detects a line voltage variation due to a calling operation at a branch device BR. A voltage controller 21 in the branch device then shifts the system from standby state to operation state, and d...

Full description

Saved in:
Bibliographic Details
Main Authors YOSHIHIRO TANIKAWA, YOSHIKAZU MINAKUCHI, YOSHIKAZU UENO, MASAHIKO AMANO, MUNEO SUZUKI, KAZUHITO KAYANOKI
Format Patent
LanguageEnglish
Published 23.05.1990
Subjects
ELECTRIC COMMUNICATION TECHNIQUE
ELECTRICITY
PICTORIAL COMMUNICATION, e.g. TELEVISION
TELEPHONIC COMMUNICATION
Online AccessGet full text

Cover

More Information
Summary:A two-wire television interphone system has a line voltage discriminator 12, in a master device MA which detects a line voltage variation due to a calling operation at a branch device BR. A voltage controller 21 in the branch device then shifts the system from standby state to operation state, and drives a call signal generator 13 in the branch device for actuation of a call signal receiver in the master device MA. The system is thus made to have a power supply circuit energized for a power supply E to the system only when required for effecting the calling operation, talking between the devices, etc. ……
Bibliography:Application Number: GB19890025471