Facsimile interface unit (FIU) enhanced capabilities negotiation
US5488653A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 27, 1992 |
| Grant date | Jan 30, 1996 |
| Priority date | — |
| Expiry date | Aug 27, 2012 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N1/33307
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An apparatus for and a method of permitting the in-band negotiation of enhanced capabilities between two or more facsimile interface units (FIUs) by using FIU capabilities control packets containing a plurality of data cells carrying information of the capability negotiation information is disclosed. In operation, a called station identification signal is transmitted from a remodulating FIU together with a special capabilities packet following the end of a line control packet. The calling FIU may issue a response agreeing to or modifying the compatible enhancements by sending its own special capabilities control packet containing compatibility negotiation information. In another aspect of the present invention, an FIU adds a set of data cells to a line control packet to minimize the possibility of data cell alignment due to degraded channel conditions. In accordance with the present invention, a unique word is selected and transmitted in the set of data cells so as to enhance the system performance and protocol tracking capability of the receiving FIU.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.