Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!usc!cs.utexas.edu!uunet!hayes!tnixon From: tnixon@hayes.uucp Newsgroups: comp.dcom.modems Subject: Re: Status of HDLC Standard (1/12/90) Message-ID: <3898.27f9baa3@hayes.uucp> Date: 3 Apr 91 11:21:07 GMT References: Distribution: comp Organization: Hayes Microcomputer Products, Norcross, GA Lines: 53 In article , mskuhn@faui09.informatik.uni-erlangen.de (Markus Kuhn) writes: > Has anybody information about the following two extentions > to HDLC: > > - Extended Transparency Options for Start/Stop Transmission > - Seven-bit Transparency Option for Start/Stop Transmission You should be able to get these PDAMs through your country's ISO national body (DIN). The original work on these proposals was done here at Hayes back in 1985, and I presented them in the standards bodies initially back in 1986. ANSI X3S3.4 decided to push first for the standardization of the basic Start/Stop HDLC (AD 1) rather than try to explain the whole package to ISO/IEC JTC 1/SC 6/WG 1 all at once. I haven't been attending meetings of either of these committees for a couple of years, but apparently the current members of X3S3.4 have followed through and submitted the additional portions of the original Start/Stop HDLC proposal to ISO for consideration. > Are there any standards (V.42ter, X.32bis, ???) in development > that use Start/Stop HDLC? CCITT Study Group VII has initiated work on adding the Start/Stop HDLC framing mode to X.25 and X.32. I do not know the current status of that work, except that I know it's not done yet. A lot of PTTs and PSPDNs are very interested in it because of the potential market for value-added services to async-only PCs (without the need to add an HDLC card and synchronous modem). > Are there any modems that use Start/Stop HDLC and convert it in > normal HDLC? I am not aware of any. Hayes V-series modems support Start/Stop HDLC in two ways: Start/Stop LAPB protocol to retrofit error control features on older, async-only modems like the Smartmodem 1200; and, Start/Stop X.25 (which is pretty useless right now, since no network supports it yet!). But they don't provide direct pass-through conversion from Start/Stop HDLC to sync HDLC. Our modems DO provide the "Hayes AutoSync" feature, which permits conversion in the modem between async and sync data streams, but the async data format is not according to 3309/AD 1 (it is simpler; no transparency required, and the FCS calculation is done in the modem). -- 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