DTMF Signaling on four-wire switched 56 Kbps Lines
US5457690A · kind A · utility
4Cited by
11References
50Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Jan 3, 1994 |
| Grant date | Oct 10, 1995 |
| Priority date | — |
| Expiry date | Jan 3, 2014 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04Q2213/13405
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
Dual tone multi-frequency (DTMF) address signaling on four-wire switched 56 kilobits per second (Kbps) service lines is obtained by determining the proper byte boundary information. An iterative learning process is used with an existing digital switching network having a call progress indication capability. The learning process steps through each possible byte alignment until the call progress protocol indicates that a proper byte alignment has been achieved. Once a paper byte alignment has been determined, that byte alignment information is retained for subsequent use, thus avoiding the need to repeat the learning process.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.