Automatic data restoral for modems
US5274697A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 22, 1993 |
| Grant date | Dec 28, 1993 |
| Priority date | — |
| Expiry date | Feb 22, 2013 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04M11/06
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
Automatically restoring data transmission by monitoring line degradation and switching to a new line (or lines) when line quality falls below a prescribed standard. Data transmission is maintained on the leased line while communication is being established on the dial line, so as not to disrupt data transmission; communication is established across two dial lines to restore full-duplex transmission; energy is maintained on the dial lines at times when data is not being transmitted to prevent a change of channel on a dial line; a signal processor, associated memory, and analog interface circuitry provide the data restoral functions; control of the restoral procedure is handled by one modem (e.g., the calling modem), and commands are sent to the other modem over either the leased or dial lines.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.