Technique for automatic identification of a remote modem
US5311578A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 7, 1992 |
| Grant date | May 10, 1994 |
| Priority date | — |
| Expiry date | May 7, 2012 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04M11/06
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
In the public switched telephone network, an originating modem can identify an answering modem, e.g., as to the type of modem it is, by detection of a low-level identification signal sent from the answering modem. The low-level identification signal is hidden within an industry standard "answer tone," e.g., a CCITT V.25 answer tone of 2100 Hz. If the low-level identification signal is detected by the originating modem, the industry standard "handshaking" procedure is terminated and a non-standard handshaking procedure is implemented. If the identification signal is not detected by the originating modem, the industry standard handshaking procedure is simply completed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.