Method and apparatus for removing FSK in-band signaling
US5768367A · kind A · utility
3Cited by
9References
4Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Oct 17, 1996 |
| Grant date | Jun 16, 1998 |
| Priority date | — |
| Expiry date | Oct 17, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04M3/428
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A circuit for use with a SCWID adjunct to remove A.C. in-band signaling tones from the voice path to a telephone apparatus serially connected to the adjunct. The A.C. signal component is carried on top of the D.C. voltage used to power the telephone. The circuit includes means to monitor the D.C. voltage level and to pass this voltage substantially unchanged to the telephone. The A.C. signal in the form of a FSK tone, received from the central office, is used by the adjunct to provide a subscriber with call feature information such as the identity of a calling party while the telephone is off-hook.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.