Method and apparatus for disabling an echo canceller
US5123009A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 26, 1990 |
| Grant date | Jun 16, 1992 |
| Priority date | — |
| Expiry date | Oct 26, 2010 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04J3/0682
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A method and apparatus for disabling an echo canceller in a digital telephone network. An originating DSU transmits a sequence of synchronization codes which are shifted by the various delays in the network. The answering DSU receives the shifted codes and determines how much adjustment is required by the originating modem in order to have byte boundaries aligned with those of the network. The answering DSU then transmits this information back to the originating DSU so that the originating DSU can adjust its transmit time to align with the byte boundaries of the network. The originating DSU then transmits byte aligned 2100 Hz tone samples in order to disable the network's echo canceller.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.