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US 4,727,572 AGranted
Telephone annunciator with low battery indication
OwnerW. W. Whitneyinventor
Life of this patent
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Abstract
A system for producing alternate summoning signals for telephones is described. The system is interposed between a conventional telephone and the telephone line. When a ringing signal occurs, the conventional ringer is silenced and replaced by a musical selection, a chime, a light display or other signal. The system is battery powered. When the battery voltage drops, the summoning signal changes to a continuous tone indicating the need for battery replacement.
Claims4
A system to be used with a telephone for producing a plurality of annunciating signals comprising:
- (a) a rectifying circuit for converting intermittent ringing signals to pulsating direct current;
- (b) a self monitoring battery power supply including adequate and inadequate battery voltage detection;
- (c) an electronic switching circuit for connecting said power supply to a primary signal producing and annunciating means upon detection of both said direct current and said adequate battery voltage;
- (d) an internal, low current oscillator and secondary producing means producing a continuous tone which is automatically activated in response to both detection of said direct current and inadequate battery voltage;
- whereby the system, when connected between said telephone and telephone line, will convert a ringing signal to a desired primary annunciating signal or to a continuous, secondary tone if the battery voltage is inadequate, either type of annunciating signal ceasing when the telephone receiver of said telephone is picked up.
2 more elements
Dependencies are inferred from the claim text.