dejong@idca.tds.PHILIPS.nl (Hans de Jong) (06/14/91)
I understand that there is standardisation underway regarding the protocol to drive fax modems via an RS-232 interface. Standards that I have heard mentioning are EIA class 2 and TR-29, having several classes (1-3). The purpose is to drive the fax modem from a Unix system. Can someone tell me: a) Which standardisation efforts are currently undertaken and what is their status? b) What is TR-29? Is it the same as EIA class 2? c) How do I get hold of the spec for EIA class 2 and for TR-29 (if it is not the same). If it is still in draft form, it is interesting anyhow. Thanks, Hans -- ------------------------------------------------------------------------------- - Hans de Jong Domain: dejong@idca.tds.philips.nl - UUCP: ..!mcsun!philapd!dejong - Philips Information Systems Apeldoorn, The Netherlands
tnixon@hayes.uucp (06/17/91)
In article <1465@idcapd.idca.tds.philips.nl>, dejong@idca.tds.PHILIPS.nl (Hans de Jong) writes: > I understand that there is standardisation underway regarding the protocol to > drive fax modems via an RS-232 interface. Standards that I have heard mentioning > are EIA class 2 and TR-29, having several classes (1-3). > The purpose is to drive the fax modem from a Unix system. Well, the purpose of the standard is to define a fax modem that uses a standard serial port and AT-type commands, so that it can be driven from just about any system, not just Unix systems. > Can someone tell me: > a) Which standardisation efforts are currently undertaken and what is their > status? > b) What is TR-29? Is it the same as EIA class 2? Telecommunications Industry Association technical committee TR-29 is the US national standards committee for facsimile devices -- the US counterpart to CCITT Study Group VIII. TR-29 has a couple of subcommittees. One of these is TR-29.2, "Facsimile DCE Interfaces", charged with defining protocols, command sets, features, etc., of computer-driven fax devices. I am a member of TR-29 and TR-29.2. TR-29.2 has divided its work on the basic fax modem standards into Classes which require increasingly more support for features within the modem. Class 1, published as EIA/TIA-578 (available from TIA and from ANSI for $16), defines the minimal level of hardware support needed in a modem to be able to support transmission and reception of faxes through a serial port. Class 2, which is about to be completed (and will be published as EIA/TIA-592), moves much more functionality into the modem, including all responsibility for conducting CCITT T.30 protocol negotiation. It is much easier to write software (for Unix or whatever) to drive a Class 2 modem than a Class 1 modem, because with Class 1 the software has to know everything about all the fax protocols and deal with the vagaries of timing and other misbehaviors present in many current fax machines. It is, by the way, completely improper to refer to the Class 1 or Class 2 standard as "TR-29". That is the name of the committee working on the standard, not the standard itself. The committee is working on MANY other things, too! For example, we're working on a Class 3 standard, which will also move some of the CCITT T.4 image handling responsibility out into the modem, allowing the modem to, for example, automatically convert PostScript or text or other printer languages to T.4 images. We're working on a "facsimile apparatus control" standard, which will give the software access to the scanner of the fax machine (for scanning images), the printer (for near laser-quality printing), the modem (for sending and receiving images, using Class 1 or Class 2 procedures), and any control or storage functions in the device. And there's a lot more coming. > c) How do I get hold of the spec for EIA class 2 and for TR-29 (if it is > not the same). If it is still in draft form, it is interesting anyhow. The chairman of TR-29.2 and editor of the Class 2 draft is Joe Decuir of Everex Systems, Inc. He can be reached at "jdecuir@attmail.com" or "75410.3114@compuserve.com". Although TIA requires you to be a member of TR-29.2 in order to "officially" get on the review list, Joe has been flexible with sending copies to people outside the USA because he knows you aren't allowed to join TIA. I caution you, of course, that the committee is still putting the finishing touches on the document, and it may still change in minor but significant ways. So, it is important that if you intend to write software for Class 2 that you keep track of the progress and buy a copy of the final, published standard from TIA or ANSI when it is completed (sometime later this year). Also, if after looking at the Class 2 document you think it deserves attention in the CCITT for consideration as an international standard, I urge you to contact the Netherlands PTT and ask them to support bringing the document into Study Group VIII (and that goes for anyone else who would like to see this become and international standard -- contact your PTT and modem manufacturers). -- Toby -- Toby Nixon, Principal Engineer | Voice +1-404-840-9200 Telex 151243420 Hayes Microcomputer Products Inc. | Fax +1-404-447-0178 CIS 70271,404 P.O. Box 105203 | UUCP uunet!hayes!tnixon AT&T !tnixon Atlanta, Georgia 30348 USA | Internet hayes!tnixon@uunet.uu.net