Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!rutgers!att!chinet!les
From: les@chinet.chi.il.us (Leslie Mikesell)
Newsgroups: comp.dcom.modems
Subject: Re: xyzmodem problems
Message-ID: <8457@chinet.chi.il.us>
Date: 15 May 89 04:23:25 GMT
References: <24404@agate.BERKELEY.EDU>
Reply-To: les@chinet.chi.il.us (Leslie Mikesell)
Distribution: usa
Organization: Chinet - Public Access Unix
Lines: 21

In article <24404@agate.BERKELEY.EDU> ked@garnet.berkeley.edu (Earl H. Kinmonth) writes:
>From an ATT 6310 running both SCO Xenix and MSDOS, I connect to a 9600
>baud leased line which goes to a Develnet switch and thence to various
>machines at UC-Davis and UC-Berkeley. xyzmodem (any of the protocols)
>work for downloads, but uploads INVARIABLY stop after 16 blocks have
>been transferred.  This is consistent over half a dozen different machines
>and several different xyzmodem packages on either end.  The problem
>occurs on a 2400 baud dialin as well.

>Any ideas?  kermit works (with mark parity).

Something in the link is set to use XON/XOFF flow control.  Packet 17
in x/ymodem will use a literal 17 (control-S) as the packet number
and hang the link.  The only control character kermit uses is
control-A for start-of-packet, others are forced into the printable
character range to avoid this type of problem.  On the 2400 dialup,
the flow control must be happening in one of the modems (not unusual
these days).  I thought zmodem was supposed to work on flow-controlled
lines, but perhaps it takes some option to allow it.

Les Mikesell