Xref: utzoo comp.unix.sysv386:9066 comp.dcom.modems:10439
Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!swrinde!zaphod.mps.ohio-state.edu!menudo.uh.edu!nuchat!steve
From: steve@nuchat.sccsi.com (Steve Nuchia)
Newsgroups: comp.unix.sysv386,comp.dcom.modems
Subject: Re: Getty for ISC/Telebit T-2500 w/autobaud via the CONNECT msg?
Keywords: Telebit, getty, autobaud, bi-directional
Message-ID: <1991Jun18.110618.16424@nuchat.sccsi.com>
Date: 18 Jun 91 11:06:18 GMT
References: <1991Jun15.030807.28565@pegasus.com> <1991Jun15.154304.25987@uunet.uu.net> <1991Jun16.021808.1704@jwt.UUCP>
Organization: South Coast Computing Services, Inc.  Houston
Lines: 28

In article <1991Jun16.021808.1704@jwt.UUCP> john@jwt.UUCP (John Temples) writes:
>had it set up that way because some older slow modems (Everex 2400 bps)
>would drop characters when receiving from the TB.  UUCP and interactive
>use were both impossible with the interface speed locked.  Does anyone
>know what causes this?

As explained to me by Telebit tech support:

There is a provision in the relevant standards that says, essentially,
that the modem-to-modem data stream is allowed to skip a stop bit time
slot every eight characters if the host-to-modem link is faster than
the modem-to-modem link.  Apparently telebit decided to take advantage
of this.  Unfortunately, if the *other* modem-to-host link is not
faster than the modem-to-modem link, and the stream is continuous,
there is no time to catch up and the buffers (if any!) overflow.

The 3b1 internal 1200 bps modem was where I first encountered this
particular problem.  There have been others.  I worked around the problem
by setting up dialer scripts that set the host-to-modem interface to
match the desired transmission speed.  I use those entries only for
connections that require them.  Uucp neighbors that have this problem
are outdial-only, since I leave speed locked for indial (and most outdial).

-- 
Steve Nuchia	      South Coast Computing Services      (713) 964-2462
	"Innocence is a splendid thing, only it has the misfortune
	 not to keep very well and to be easily misled."
	    --- Immanuel Kant,  Groundwork of the Metaphysic of Morals