Path: utzoo!news-server.csri.toronto.edu!torsqnt!hybrid!scifi!bywater!uunet!hayes!tnixon
From: tnixon@hayes.uucp
Newsgroups: comp.dcom.modems
Subject: Re: Another 9600 protocol!
Message-ID: <3857.27e0a4d5@hayes.uucp>
Date: 15 Mar 91 10:41:25 GMT
References: <1991Mar2.005717.14483@qiclab.scn.rain.com> <1991Mar7.053032.5393@melb.bull.oz.au>
Organization: Hayes Microcomputer Products, Norcross, GA
Lines: 32

In article <1991Mar7.053032.5393@melb.bull.oz.au>,
kmp@melb.bull.oz.au (Kevin M Payne) writes: 

> Is there any standard, defacto or otherwise for 9600 (V29) modems. 
> i.e. turning the line around etc.   Do any modems provide a buffered
> (and assumed flow control) V29 protocol that turns the line around
> but yet is transparent to the user?  If such a standard exists,
> where can it be found? 

There is no formal standard, promulgated by an accredited and 
recognized standards body, in this area.  V.29 is only standardized 
for duplex synchronous communications on leased lines; it is also 
used for simplex transmission of image data in Group 3 facsimile.  
No other use is standardized.

Nevertheless, a number of companies produce fast-turnaround 
half-duplex V.29 modems for use on multidrop leased lines and 
two-wire voice-grade dial-up lines.  Most of these are standard 
synchronous half-dupelx interfaces.  Microcom has defined MNP Class
6, which is a ping-pong modulation scheme based on V.29 that 
provides error-control, flow control, and buffering to give the 
appearance of a duplex asynchronous connection (similar to Hayes 
V-series 9600 ping-pong modulation, but the Hayes modulation is 
based on V.32 constellation and coding rather than V.29).  To the 
best of my knowledge, only Multitech, other than Microcom, ever made 
an MNP6-compatible modem.

-- 
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