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Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!tut.cis.ohio-state.edu!att!cbnews!vjg
From: vjg@cbnews.att.com (vincent.j.guinto)
Newsgroups: unix-pc.general,comp.sys.att
Subject: Re: UMODEM problem
Summary: Problem Solved!
Message-ID: <1991Jan2.153818.10924@cbnews.att.com>
Date: 2 Jan 91 15:38:18 GMT
References: <1991Jan1.211151.19163@cbnews.att.com> <37480@cup.portal.com>
Followup-To: unix-pc.general
Organization: AT&T Bell Laboratories
Lines: 58

vjg@cbnews.att.com (vincent.j.guinto) (ME!) in <1991Jan1.211151.19163@cbnews.att.com>
> writes:
> 
> 	I use umodem to transfer files between computers at work and
> 	my 7300 (OS version 3.5) at home, at 1200 baud. I've also used
> 	it at 9600 baud.
> 
> 	The transfer works just fine from the mainframe to the 7300,
> 	but when transferring backwards from the 7300 to the mainframe,
> 	the transfer always fails at the 18th segment (or block, or 
> 	whatever term umodem uses to divide up a file).
> 
> 	This failure has occurred at both 1200 baud over a phone line
> 	and at 9600 baud via a serial port, and occurred on two different
> 	mainframes, which makes me inclined to believe that the problem
> 	is on the 7300. I've used both text and binary transfer modes.
> 
> 	[...]
> 


Thanks to a couple email responses I received last night, I was able
to solve this problem and get umodem to work for me.

The general concensus was that it was a flow control problem, due to
something in the header of the 19th segment (or 18th, depending on
the person responding) looking an awful lot like a <CTRL> S character.

I turned of flow control on my 7300, and it still croaked. I then
turned off flow control on the mainframe I was trying to send the
files to, and it worked!

Somebody mentioned that they had to buy a special phone line to get
around this flow control problem. Fortunately I'm dialing into a 
fairly smart network (AT&T's Datakit, to plug one of my company's
products), and I can turn flow control on/off at my whim once I'm
connected.

So, thank you all for your help and advice. Shutting off the flow
control worked just fine, and the problem is solved!

P.S. For those who recommended using kermit instead, I looked and
looked and couldn't find kermit on the mainframe. Why, I don't know,
but it just ain't there (rats!).

Someone deemed my desire not to use HDB as "shortsighted." Can anyone
clue me in on what benefits I'll see by using HDB? I don't receive
any calls into my 7300, and don't normally poll for email or any of
those other things you can do with uucp, mostly because I don't use
the 7300 all that much anyway. I suspect that for a low-powered user
like myself, something like HDB wouldn't pay off in a cost/benefit
analysis. Any opinions? (now that's a silly question, I'd be surprised
if there WEREN'T any opinions!)

----------------------------------------------------------
Vince Guinto                                 att!cblph!vjg
AT&T Bell Laboratories                  Opinions are mine,
Columbus, OH                                    not AT&T's