Facsimile detection system and method
US5519768A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 1, 1994 |
| Grant date | May 21, 1996 |
| Priority date | — |
| Expiry date | Dec 1, 2014 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04Q2213/13545
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
In connection with enhanced telephone service, such as personal number service, the detection of whether an incoming telephone call is a facsimile transmission or an ordinary voice call is improved by a utilizing a modified ring back signal during the time in which the service circuit node of the telephone system is attempting to detect the presence of the calling tone (CNG signal) of the sending facsimile machine. Particularly, the ring back signal is modified to increase the off time of the ring back signal to be greater than the period of the CNG signal. Where the CNG signal is a periodic signal with a period of 4 seconds with a 0.5 on time and a 3.5 off time, the modified ring back signal has a period of 7 seconds with a 2 second on time and a 5 second off time.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.