Intermittant modem failure? (fwd)

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Hi,

Jon Lewis wrote:
> On Sat, 11 Oct 1997, Gert Doering wrote:
> > > This is happening with Digicom rack modems (DSI MultiAccess Communications
> > > System) which are supposed to be "industrial" type modems rather than
> > > consumer grade.
> > 
> > Should be OK then.
> 
> Should be...though we've been having a lot of trouble with Digicom ports
> locking up permenantly (requiring manual reset) after or during sessions. 
> At that point they make really weird sounds (if I tap into the line with a
> telco test set) almost as if they got stuck in some sort of retrain. They
> keep coming out with hardware and firmware patches trying to fix that.

Hmmm. Doesn't sound too promising. (Sounds like ZyXEL in the early
1496-days - new firmware once a week - but those times are *years* past).

> > This could be a problem of two DTR drops in quick succession. Please try
> > setting "toggle-dtr no" in mgetty.config, and check whether it goes away.
> 
> I tried that a few days ago. The Digicoms seemed happy with it, 

Good.

> but the USR MP's were not. I think the problem there was the USR's are 
> doing a reset on DTR drop after each session, and that reset seems to 
> take a lot longer than the reset on DTR drop that should happen when 
> mgetty does it...so mgetty sends the init string early and the MP 
> modems miss it.

I find this quite astonishing. We have a couple of USR Courier modems
connected to some AIX machines here, and they usually have no problems
whatsoever with DTR drops. On some boxes, the modems locked up
occasionally, but after setting "toggle-dtr no", we never had any problems
anymore.

You do have the latest USR firmware, do you`

gert

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Gert Doering - Munich, Germany      gert@greenie.muc.de
fax: +49-89-3545980     gert.doering@physik.tu-muenchen.de
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