Telephonic communications – Telephone line or system combined with diverse electrical... – To produce visual-graphic copy
Patent
1991-11-21
1994-02-22
Ng, Jin F.
Telephonic communications
Telephone line or system combined with diverse electrical...
To produce visual-graphic copy
379102, 379 39, 379 40, 340531, 340545, H04M 1100, H04M 1104, G08B 100, G08B 1308
Patent
active
052895343
ABSTRACT:
A door phone controller has a door ajar feature for alerting a user that a door was left open. The door phone controller accommodates the door ajar feature in several different ways depending upon how it is configured to interface with the central office line. If the door phone controller is configured to interface with the central office line as an individual station, then when a door is left open, the controller alerts the user via auxiliary alert contacts specifically provided for activating a customer chime. When the door phone controller is configured as a ring-down station, the door phone controller alerts the user that the door was left ajar by dialing a pre-programmed telephone number and sending a door ajar tone. If the door phone controller is configured as an interface with a trunk port, then when the door is left open, the controller alerts the user by ringing the trunk line and also energizing the auxiliary alert contacts. The user can both enable and disable the door ajar features via the telephone interface.
REFERENCES:
patent: 4521645 (1985-06-01), Carroll
patent: 4760593 (1988-07-01), Shapiro et al.
patent: 4764953 (1988-08-01), Chern et al.
patent: 4920333 (1990-04-01), Barr et al.
patent: 4943997 (1990-07-01), Chang
patent: 5140308 (1992-08-01), Tanaka
Callaway Randy A.
Kennedy Michael
Lester James W.
Wagner Randall M.
Chan Jason
Harris Corporation
Ng Jin F.
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