From: ohanusi anthony (ohanusi@xxxxxxxxxxxxxxxxx)
Date: Mon Oct 22 2001 - 04:05:41 GMT-3
I am using dialup modem to simulate isdn line here.
The cable should be a straight tru .You can use cisco roll over cable and a
rolled db25 to
>RJ45 adapter ( CAB-5MODEM) to simulate straight tru
Regards
>The connection should be straight through from the router to the modem (DTE
>to DCE).
>
>Len Tuc
>
>----- Original Message -----
>From: "Jay Hennigan" <jay@west.net>
>To: <ccielab@groupstudy.com>
>Sent: Sunday, October 21, 2001 4:44 PM
>Subject: Re: HELP! Analog modems on aux ports
>
>
> > On Sun, 21 Oct 2001, Chuck Church wrote:
> >
> > > Hey all,usin
> > >
> > > Sorry about yelling on the subject line, but I'm getting quite
> > > frustrated with my modems on aux ports. I've got a variety of 2500
>routers,
> > > with rolled cables connecting to 2 USR 56kb modems. Autoconfigure for
>the
> > > modems keeps giving me 'deb confmodem' output like this:
> > >
> > > 01:40:56: TTY1: detection speed (300)
>response ---~# }}"%%}&'i}"'}"(X~---
> > > 01:40:56: TTY1: No modem found
> > > 01:40:43: TTY1: detection speed (1200)
>response ---~# }}"%%}&'i}"'}"(X~---
> > > 01:40:56: TTY1: detection speed (300)
>response ---~# }}"%%}&'i}"'}"(X~---
> > > 01:40:56: TTY1: No modem found
> >
> > [snippage]
> >
> > I think I'd lose the autoconfig and go with a chat script. Modems will
> > usually set their DTE speed to whatever speed the last AT command was
> > received.
> >
> > Try reverse telnet to the AUX port at a speed of 38400 and type ATZ,
> > see if you get back an "OK" from the modem. Then once you've got it
> > happy, guve the modem an "AT&W" to save it to the modem. If the AUX
> > port can go higher like to 57600 or 115200, then go with that. It sounds
> > as if hte router is trying to autonegotiate with the modem, and the modem
> > is also trying to auotnegotiate with the router, and neither is happy.
> >
> > One thing that's puzzling is that the same garbage string comes back at
> > different speeds. I would expect it to be different.
> >
> > > They worked once, and I was able to ping across the async ports, but
> > > when the call hung up, they started doing this again. Does anyone have
>some
> > > tips on doing reliable DDR over modems, including dip switch settings on
>the
> > > modems. They're Sportsters.
> >
> > One way to do it is to set the modems DIP switches to give responses and
> > go with a chat script to parse those responses. Another way which won't
> > quite simulate ISDN because you won't have a dialer string is to set the
> > modem for DTR dialer so that when the router raises DTR, the modem dials
> > a number pre-programmed into the modem, and you suppress the modem output
> > back to the router so the router doesn't get confused by the status
> > messages from the modem. Not quite as nice for lab prep because you don't
> > have the dialer string.
> >
> > I can't give exact advice on the dip switches, but things to check are
> > whether the modem echoes commands, and whether it gives response codes and
> > in what form. ATE? and ATQ? are at least two of what you want to play
>with,
> > or they may be replaced by dipswitches.
> >
> > First configure things to reverse-telnet to the modem on the AUX port and
> > see if you can talk to it and get it to dial. Then get fancy.
> >
> > > If I plug my PC into one of the modems, it
> > > responds to AT commands no problem. But the routers just get back
> > > gibberish. Since I got pings across once, I know my async interface
> > > settings are ok. It's just the configuration on the aux line. Any help
>is
> > > appreciated. This is driving my nuts...
> > ^^^^^^^^^^^^^^^^^^^^^^^^^^
> >
> > Sounds painful.
> >
> > --
> > Jay Hennigan - CCIE #7880 - Network Administration - jay@west.net
> > NetLojix Communications, Inc. - http://www.netlojix.com/
> > WestNet: Connecting you to the planet. 805 884-6323
Ohanusi Anthony CCNA,CCNP,CCIE Written.
WAN Engineer
Network Solution, A Schlumberger Company
Email : <ohanusi@lagos.sns.slb.com>
Phone : 234-1-2610446 EXT 3230
Fax : 234-1-2621034
Learn to qualify your statement
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