Controllable telephone annunciator
US4856055A · kind A · utility
Inventor
Key dates
| Filing date | Jul 25, 1988 |
| Grant date | Aug 8, 1989 |
| Priority date | — |
| Expiry date | Jul 25, 2008 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S379/914
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
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 th…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.