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Invalid Config Register Value


One of my engineers had to break a password on a 2600 Router, so he accessed the ROM mode and instead of entering the value 0x2142, he entered 0x2412

I am not quite sure of the value that he entered. All I know for sure that he entered an incorrect value.

Now when I access the console using Hyperterminal, I receive invalid character.

I am unable to telnet to the Router since telneting is denid.

I apreciate if someone could tell me how I can change back the register to at 0x2102 since the output is not legable.



Community Member

Re: Invalid Config Register Value

Hi Ahmed,

your engineer has changed the config register in a way that the console speed has been altered. To be able to get "understandable" characters back on your terminal sessions, you need to synchronize the speed setting between your router console port and the terminal program your are using.

The speed values that can be set, using the bits of the configuration register are 1200, 2400, 4800 & 9600 bps. Use the trial and error method to discover the new setting and then you will be able to communicate with your router and change the config register value to the one you need.

Don't forget to disconnect and then connect back your terminal session for the new speed setting to be effective.

Hope this helps.


Community Member

Re: Invalid Config Register Value

config-registers 0x2102

Community Member

Re: Invalid Config Register Value

Hi Ahmed.

Your engineer changed the config register to a value that didn't change the console speed from the usual 9600 bps (bits 5, 11 and 12 are set to 0), but he set bit 4 which is reserved... If you still can't access the router, I suggest you open a TAC case.

If he had changed any bit that controls the console speed (bits 5, 11 and 12), the trial and error method already suggested by Wassim would work.



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