System and method for detecting customer premises equipment alerting signals
US5974138A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 14, 1999 |
| Grant date | Oct 26, 1999 |
| Priority date | — |
| Expiry date | Jan 14, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04M1/573
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A system for, and method of, detecting a customer premises equipment ("CPE") alerting signal ("CAS") on a telephone line that is carrying near-end audio traffic and CPE embodying the same. The system includes: (1) an echo cancellation circuit, coupled to the telephone line, that detects an outbound component of the near-end audio traffic and produces, in response thereto, an echo canceling signal, (2) a combinatorial circuit, coupled to the telephone line and the echo cancellation circuit, that applies the echo canceling signal to an inbound component of the near-end audio traffic to produce a resulting signal having the near-end audio traffic substantially removed therefrom and (3) a CAS detector, coupled to the combinatorial circuit, that detects the CAS in the resulting signal, the echo cancellation circuit and the combinatorial circuit cooperating to increase the reliability of the CAS detector.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.