Ring signal discriminator
US4720853A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 9, 1987 |
| Grant date | Jan 19, 1988 |
| Priority date | — |
| Expiry date | Mar 9, 2007 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S379/903
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
An improvement to automatic answering and call forwarding features used in telephone communications which allows a user to remotely activate, modify, and deactivate these features. The improvement describes a transformerless means for coupling signals to and from the telephone line without compromising the operation of the telephone line. The apparatus employs a microprocessor controller (11) with memory (12), a tone encoder (15), a tone decoder (14), a voice synthesizer (16), a timer (13), a cassette interface (17), an RS232C interface (20), a switching matrix (21), and a line interface (22). Audio, pulse dial, and tone signals are routed among the components and the telephone line (51) by the switching matrix (21) and line interface (22). The line interface (22) provides a transformerless means for coupling signals to and from the telephone line (51) and also analyzes the status of, and signals present on, the telephone line (51).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.