Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!usc!elroy.jpl.nasa.gov!decwrl!sgi!vjs@rhyolite.wpd.sgi.com
From: vjs@rhyolite.wpd.sgi.com (Vernon Schryver)
Newsgroups: comp.sys.sgi
Subject: Re: modem trouble
Summary: RTS/CTS flow control
Keywords: modem
Message-ID: <106257@sgi.sgi.com>
Date: 25 May 91 18:06:24 GMT
References: <1991May25.021412.6558@gpu.utcs.utoronto.ca>
Sender: guest@sgi.sgi.com
Organization: Silicon Graphics, Inc., Mountain View, CA
Lines: 30

In article <1991May25.021412.6558@gpu.utcs.utoronto.ca>, topix@gpu.utcs.utoronto.ca (R. Munroe) writes:
> I'm having a bit of strange trouble with a Hayes Ultra 9600 Smartmodem
> hooked up to a PI 25.  I can dial out O.K.  I also have no trouble
> dialing in - the modem connects, I get my login prompt, etc.  The trouble
> starts when I issue a command who's output is more than 5 or 6 lines.
> For example, if I issue an 'ls' command, the first 4 lines of my 
> directory listing print out fine.  The next line is completely garbled
> and the following lines don't print.   ....

I assume a Hayes Ultra 9600 is a v.32 compatible modem.
You don't say what sort of garbling happens.  However, I bet it's missing
characters.

I bet the problem is that:
  -your modems are talking to each other slower than to the IRIS
     +modems using 2400 bits/sec (v.22) and IRIS-modem interface is at
	9.6 or 19.2 b/s
     +modems using 9600 bits/sec (v.32) and IRIS-modem interface at 19.2 b/s
  -the modem is not doing any flow control because
    +the cable is wrong  (not 7 correct wires)
    +not using the ttyf* name
    +modem is not capable of or configured to use RTS/CTS flowcontrol
    +IRIS and/or modem not set to use in-band, XON/XOFF flow control
  -as a result of the speed mismatch, the IRIS is overrunning the modem buffer.

Please note that fix-hayes is for the ancient "Hayes 2400 Smartmodem."
I have no idea what effect it has on this new modem.


Vernon Schryver,   vjs@sgi.com