Communications: electrical – Systems – Selsyn type
Patent
1989-11-14
1991-07-16
Crosland, Donnie L.
Communications: electrical
Systems
Selsyn type
340310A, 358 85, 358 86, 358108, 379 53, 379171, H04M 1104, H04N 710
Patent
active
050328204
ABSTRACT:
Two-wire television interphone system is arranged to discriminate by a line voltage discriminator incorporated in a master device a line voltage variation due to a calling operation on the side of a branch device, to actuate a voltage controller in the branch device to shift the system from standby state to operation state, and to drive a call signal generator in the branch device for actuation of a call signal receiver in the master device. The system is thus made to have a power supply circuit energized for a power supply to the system only when required for effecting the calling operation, talking between the both devices, and so on.
REFERENCES:
patent: 3723653 (1973-03-01), Tatsuzawa
patent: 3816662 (1974-06-01), Shaver et al.
patent: 3999006 (1976-12-01), Takeuchi et al.
patent: 4427847 (1984-01-01), Hofmann et al.
patent: 4645872 (1987-02-01), Pressman et al.
patent: 4893326 (1990-01-01), Duran et al.
patent: 4932047 (1990-06-01), Emmons et al.
Tektone, "Tek-View VM-Series Video Intercom" 6-1988.
Sound and Communication, Tektone, "Mobile Communications" 12-1980.
Amano Masahiko
Kayanoki Kazuhito
Minakuchi Yoshikazu
Suzuki Muneo
Tanikawa Yoshihiro
Crosland Donnie L.
Matsushita Electric & Works Ltd.
LandOfFree
Two-wire television interphone system does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Two-wire television interphone system, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Two-wire television interphone system will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-133738