eli@pws.bull.com (Steve Elias) (12/13/90)
hello and welcome to comp.dcom.fax. this group is for discussing fax hardware, software, and protocols. it is intended as a replacement for alt.fax. a few words about something interesting that's happening in the world o fax: Group IIIbis. apparently this enhancement to the group III standard is rather controversial. the gist of the proposal is to enhance to Group III standard to include digital transmission media up to 64kbps, and the Group IV encoding standard, which takes advantage of reliable digital media. France and Japan oppose Group IIIbis. does anyone know how the US faxmodem chip makers are standing on this issue? (rockwell, signetics, ?) i've also heard about proposals to enhance group III with the resolutions supported by group IV (400x400, for one). this presents an interesting technical problem for the fax board and fax machine manufacturers: resolution conversion on the fly. /eli -- /* eli@spdcc.com eli@pws.bull.com 617 932 5598 508 294 7556 */
jpal@pyrnova.pyramid.com (John Palasz) (12/14/90)
Hello, Now that we're welcome, I'm probably going to ask a common question. I'm interested in learning more (quite a bit more) about the fax protocols and I would appreciate any suggestions on books, articles etc that would get me to a detailed technical understanding of the protocols and how they are implemented. Even if this help is just a phone number of someone to call where I may get the "standard document" which describes the protocol in mundane detail. thanks in advance. I am glad this group exists.....jpal John G Palasz(Systems Engineer).....................Pyramid Technology pyramid.com!jpal ....................500 108th Ave. NE(Suite 800) Bellevue, WA 98004 (206)646-7368
hrs1@cbnewsi.att.com (herman.r.silbiger) (12/16/90)
In article <19714@know.pws.bull.com>, eli@pws.bull.com (Steve Elias) writes: > hello and welcome to comp.dcom.fax. this group is for discussing > fax hardware, software, and protocols. it is intended as a > replacement for alt.fax. > > a few words about something interesting that's happening in > the world o fax: Group IIIbis. apparently this enhancement to > the group III standard is rather controversial. the gist of the > proposal is to enhance to Group III standard to include digital > transmission media up to 64kbps, and the Group IV encoding standard, > which takes advantage of reliable digital media. > > France and Japan oppose Group IIIbis. does anyone know how the US > faxmodem chip makers are standing on this issue? (rockwell, > signetics, ?) > > i've also heard about proposals to enhance group III with the > resolutions supported by group IV (400x400, for one). this presents > an interesting technical problem for the fax board and fax machine > manufacturers: resolution conversion on the fly. > > /eli > At the first meeting of Study Group VIII the US and the UK submitted contributions proposing to enhance G3 by providing a 64 Kbit/sec interface, while maintaining backward compatibility with G3 on the analog network. The proposal was supported by several other countries, such as Canada, the USSR, Brazil and Switzerland. It was strongly opposed by Japan, Germany and France. The US proposal was developed in EIA/TIA TR-29, the Facsimile Standards Commitee, ba`sed on an AT&T contribution. Modem and chip manufacturers such as Rockwell and Hayes are represented on this committee. In March 1990 the US submitted a more detailed proposal, an the USSR also submitted a detailed proposal on the protocol. The Rapporteur for G3 is from France, which made it difficult to discuss the proposals on their merit. An associate Rapporteur wa therefore appointed by the Chair of SG VIII, to investigate and report on the problem. This rapporteur, Alberto Guiseppini from the Italian Telecom Ministry, issued his report at the September meeting of DG VIII, and the report made it clear that G3-64Kbit/sec (G3bis is not an official designation) is both technically feasible but also more efficient than G4, especially in the presence of errors and satellite delay. The US and UK also had detailed technical proposals at that meeting. Study Group I, which is charged with service recommendations, agreed in November that the G3 technical recommendations could be amended to provide for 64Kbit/sec transmission, although Germany and France still oppose it. A first meeting of the G3-ISDN group to draft amnedments to Rec. T.30 will meet in January in the UK. Guiseppini's timetable calls for approval in March 1992. The UK proposal is for the use of ISDN's full duplex capability to do the error correction. The US proposal makes smaller changes to T.30. Proponents of G3-ISDN claims that a G3 machine with ISDN interface should not be much more expensive that a normal G3 machine. Amendments to T.30 were approved in September to allow the use of T.6 encoding (originally for G4) when the ECM (error correction mode) is used, and for 14.4 Kbit/sec V.33 and V.17 modems. It is expected that the higher resolutions (upt to 400x400 ppi) will be approved next fall. Herman Silbiger hsilbiger@attmail.com