Controllable telephone annunciator

Details Controllable telephone annunciator Controllable telephone annunciator

1988-07-25

1989-08-08

Dwyer, James L.

Telephonic communications

Supervisory or control line signaling

Signal reception at substation

379386, 379387, H04M 1102

Patent

active

048560553

ABSTRACT:
A circuit is connected to the line of a telephone for disabling the ringer (22) of the telephone and supplying, instead of the regular ring signal, any of a plurality of predetermined alternative signal melodies or voice messages. The circuit comprises a ring detector (24) for detecting the incoming rings, a relay (26) which is responsive to the rings for turning off the regular ringer, a signal library (28) for storing the predetermined alternative signals, and an amplifier (32) and a speaker (34) for reproducing the signals in an audible manner. Also a current detector (30) is provided to detect direct current flow when the telephone is answered and thereupon disable the alternative signal source. The alternative signal may be selected by the telephone user with a switch on the signal library, or by supplying predetermined tones to the circuit, either by the caller or the called party (FIG. 4). If by a caller, the caller would use the dual-tone dialing tones to select the alternative signal just after the connection is made and preferably before ringing started. The circuit contains a DTMF (dual-tone, multi-frequency) detector (36) to produce binary output codes in response to the DTMF tones, and a selection logic circuit (38) would be provided to select the signal in the signal library. The system can be alternatively implemented by means of a programmed microprocessor (FIG. 6).

REFERENCES:
patent: 4480153 (1984-10-01), Festa
patent: 4727572 (1988-02-01), Whitney
U.S. Statutory Invention Registration, Reg. No. H118, Biggs et al., 9-2-86.

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