Text transmission using DTMF signalling
US5699417A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 21, 1995 |
| Grant date | Dec 16, 1997 |
| Priority date | — |
| Expiry date | Apr 21, 2015 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04M1/575
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A method and system for transmitting text information using multifrequency signals is provided. A switching center transmits a first multifrequency signal indicating the start of a text transmission. A receiver unit receives the first multifrequency signal and prepares to receive text information. The switching center transmits to the receiver unit a second and third multifrequency signals after the first multifrequency signal. The second and third multifrequency signals contain information corresponding to a text character. The receiver unit receives the second and third multifrequency signals and determines the text character transmitted. The switching center transmits a fourth multifrequency signal to the receiver unit indicating the end of the text transmission.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.