Modem to 2811 Console

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Jan 28th, 2008
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Hi all,

I am wondering if someone may be able to point out where I'm going wrong.

I want to be able to see/user the boot cycle/ROMMON mode of a 2811 router, remotely.

As I understand it, the only way to achieve this is with an analogue modem connected to the Console port.

I'm doing the testing here with a Cisco 2651 as it's the only router I have available to me locally, though as most of the configuration is modem-side, I feel that it shouldn't make much of a difference..

I'm using a Hayes External Serial modem, connected to the Console port with a Cisco-provided 25pin D -> RJ-45 roll-over.

However, after using this ( guide, I've not had any success. The basic principles appear the same as with a router, but when I dial in, the modems handshake and connect but HyperTerminal displays nothing. There is no output at all UNLESS I enable the 'post-dial window', and then I can control the console. My issue is that this is not a native console - there's no xmodem support and I wouldn't have a clue how to duplicate this work-around in another client (minicom or screen, for example.)

I've noticed that the S37=9 (listed in the guide as the setting for 9600kbps) is not a value that is saved in the current profile. Perhaps the Hayes set has been updated since the article was written. Does anyone know a better way to set this? I have found a way of forcing V.32, which is 9600, but .. is it correct?

Here is the current profile stored on the modem:


B1 E1 L1 M1 N0 Q0 T V1 W2 X4 Y0 &C1 &D0 &G0 &J0 &K0 &Q5 &R1 &S0 &T5 &X0 &Y0

S00:001 S01:000 S02:043 S03:013 S04:010 S05:008 S06:002 S07:050 S08:002 S09:006

S10:014 S11:085 S12:050 S18:000 S25:005 S26:001 S36:007 S38:020 S46:138 S48:007


(Note that I set ATE0 and ATQ1 when testing, but these were flipped for the purpose of viewing the config ;))

Here is the config from the router:

line con 0

exec-timeout 5 0

logging synchronous

I *think* this is a problem with the speed not detecting the speed of the console properly, but I'm not experienced enough with modems at this level. I've even consulted my CCNP2 book, only to find that it concentrated more upon the Aux port.

I can get modem -> Aux working, but that's just not flexible enough (despite its advantages.)

If anyone can help, I'd be extremely grateful. If you require any more information, I'll be happy to provide it! :)



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Collin Clark Mon, 01/28/2008 - 10:51
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When you connect the modem to the console port and dial the modem, what happens? You should have a login prompt or a router> prompt. There is no configuration (other than security) on the console port to make this work.

firebadger Mon, 01/28/2008 - 11:07
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As stated, I don't actually get this. I was fairly certain that this was what I should see in the HyperTerminal output, so realised I'd done something wrong when it only worked in the 'post-dial terminal window'.

I'm quite baffled how the post-dial window works, and the standard HyperTerminal 'window' doesn't.

Collin Clark Mon, 01/28/2008 - 11:29
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I never use HyperTerminal, do have another terminal app you can use (like Putty)?

firebadger Mon, 01/28/2008 - 12:24
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It *should* work as you describe in HyperTerminal, to the best of my knowledge.

I will give PuTTY a try tomorrow. But I didn't know dialing via PuTTY was possible! :)


Collin Clark Mon, 01/28/2008 - 12:27
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Let me verify, I actually use SecureCRT, but Putty is free!


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