Communications: electrical – Systems – Call station
Patent
1976-01-29
1977-11-08
Caldwell, Sr., John W.
Communications: electrical
Systems
Call station
340164R, 340168B, 340147SY, 340171R, 340311, 325 64, G08B 108, H04M 1102
Patent
active
040577902
ABSTRACT:
A system for use especially by the infirm or elderly for summoning the help of others who are located a distance away. The system includes a radio-type transmitter adapted to be carried in a pocket of the elderly person, and a receiver/decoder and signalling device located at an adjoining area from which signals for help or assistance can be readily observed. The transmitter unit can be activated by means of a switch or button, and emits short bursts of a modulated signal having a unique, preselected frequency. The signal is picked up by the receiver and demodulated by a detector. The decoder comprises a sensing circuit, including a gated, resettable counter which measures the frequency of the detected signal. Means connected with the counter output trigger an alarm when the transmitted frequency having the proper modulating signal is received. By the above arrangement a plurality of similar units can be disposed in the same area and operated with slightly different modulating frequencies without causing interference or interaction between them.
REFERENCES:
patent: 2951230 (1960-08-01), Cadden
patent: 3384873 (1968-05-01), Sharma
patent: 3510777 (1970-05-01), Gordon
patent: 3684964 (1972-08-01), Bright et al.
patent: 3768090 (1973-10-01), Williams
patent: 3798549 (1974-03-01), Ollinger et al
patent: 3851251 (1974-11-01), Wigner et al.
patent: 3852713 (1974-12-01), Roberts et al.
patent: 3855575 (1974-12-01), Leuschner
Fleming George William
Paul Alfred N.
Caldwell Sr. John W.
Crosland Donnie L.
Lehmann H. Gibner
Lehmann K. Gibner
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