Connect Modem to Router AUX

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Jun 17th, 2009
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Need to set up a modem connection to console server for remote maintenance... Does not work need help..

Modem is Robotics 28800 Fax modem, test router is 2621 with AUX.

At 2621 i got "1d02h: TTY65: detection speed (38400) response ---OK---

1d02h: TTY65: Modem type is usr_sportster

1d02h: TTY65: Modem command: --AT&F&C1&D2&H1&R2&M4&K1&B1S0=1H0--

1d02h: TTY65: Modem configuration succeeded

1d02h: TTY65: detection speed (115200) response ---OK---

1d02h: TTY65: Done with modem configuration" Looks like the router can detect modem, so the cabling between 2621-AUX to modem should be fine..


line aux 0

password cisco

modem InOut

modem autoconfigure discovery

transport input all

stopbits 1

speed 9600

flowcontrol hardware


from my laptop I can dial-in modem, heard the initial dial-in noise(zzzzzzz), but can not open 2621 console windows, keeping dialing tone for couple of times then go to busy signal (disconnect) .... ???

Any idea, is any special setting at HyperTerminal??? The Robotics modem has eight dip switches at back, does the dip have special sequence for modem connection??


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Collin Clark Wed, 06/17/2009 - 13:02
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If this is for remote maintenance is there a reason you can't connect the modem to the console port? Makes life easier IMO.

slmansfield Wed, 06/17/2009 - 18:23
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Connecting the modem to the console port of the router requires specific configuration of the modem which will probably not work with any other device without setting the modem back to its defaults.

If the aux port is used you can connect the modem as is from out of the box, you just want to enable Auto Answer, which I believe is not a default setting on the US Robotics modem. Check the manual for the dip switch setting for Auto Answer.

The advantage of using the console port (which is what I also prefer) is that if the router is "brain dead" (e.g., has lost its config), you can still dial into it. Without the router configuration you cannot dial in via the aux port.

Here's a document on CCO that steps you through the process of configuring the aux port for remote access.

In case you want to take Collin's (and my) advice, here's the URL for configuring a US Robotics modem to connect to the console port.


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