Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!wuarchive!uunet!hayes!tnixon
From: tnixon@hayes.uucp
Newsgroups: comp.dcom.fax
Subject: Re: Command Set Standard for Fax Boards
Message-ID: <3697.276dfe71@hayes.uucp>
Date: 18 Dec 90 11:33:04 GMT
References: <9012162229.AA29892@tut.cis.ohio-state.edu>
Organization: Hayes Microcomputer Products, Norcross, GA
Lines: 55

In article <9012162229.AA29892@tut.cis.ohio-state.edu>,
yjj@SIRIUS.CTR.COLUMBIA.EDU (Yuan Jiang) writes: 

> There was a posting on comp.dcom.modem several month ago
> about the setting up of a committee to work out the
> standard command set for fax boards.  Does anyone know
> how they are doing?  What is the status? I'd like to see the
> job is done as soon as possible so that I can upgrade
> my fax board.

The committee you're asking about is TIA (Telecommunications 
Industry Association) technical subcommittee TR-29.2 on Facsimile 
Digital Interfaces.  

The work on a Fax DCE command set standard is progressing very well. 
The "Service Class 1" standard, which specifies a very minimal level 
of hardware support with the T.30 protocols being performed in the 
PC software, has been published as ANSI/EIA/TIA-578, and is 
available through EIA Standards Sales.

The "Service Class 2" draft standard specifies a higher level of 
function in the Fax DCE.  The T.30 fax control protocol is largely 
implemented in the modem, but the T.4 image data handling is still 
performed in the PC software.  The Class 2 standard has been through 
one round of industry ballot, and received a few "no" votes due to 
concerns about the complexity of the document, the partitioning of 
T.4 functions between the modem and PC, and the lack of a way to 
recovery from data overrun errors on the serial interface.  These 
concerns are being addressed now, and the document should be going 
out for another round of balloting in the spring.  The hope is still 
to have a standard published by summer.

"Service Class 3" is still very much in the definition phase.  The 
concept is that most or all of T.4 (image encoding) functions would 
be placed in the modem, with the PC able to provide ASCII text, font 
designs, graphic images in their native formats (PostScript, PCX, 
etc) directly to the modem.  There are so many issues in this 
project, it's hard to say when it will be completed.  There are 
quite a few people who feel this level of functionality should simply 
remain in the PC software, and that TR-29.2 should not go beyond 
Class 2.

There's no guarantee that you'll be able to "upgrade" your fax board 
to the standard.  Many fax boards are quite simple, with virtually 
no intelligence on them at all (they simply serialize the interface 
between the modem chipset and the PC).  Others are quite 
intelligent, with powerful microprocessors and lots of memory.  No 
manufacturer is obligated to upgrade any existing product to be 
compliant with the standard.

-- 
Toby Nixon, Principal Engineer    | Voice   +1-404-449-8791  Telex 151243420
Hayes Microcomputer Products Inc. | Fax     +1-404-447-0178  CIS   70271,404
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