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Continous reboot of 7912 IP phones

On one of our subscribers, the 7912 phones are experiencing countinous reboot. They were all working fine yesterday. A few seconds after they come up, they start re-configuring again. All the other models are doing just fine. Can anyone please tell what the problem here is and what needs to be done to resolve this issue?

Will rate helpful posts.


Re: Continous reboot of 7912 IP phones


Have you tested new phone loads on these phones to make sure they work and are there any errors on the phone when it boots?

Also, are different phones models patched into the same switch, or are the phones in this office (plugged into this switch) primarily 7912's?

Are there any errors in the event logs and CCM traces to determine why they are failing (TFTP etc.)?

Cisco Employee

Re: Continous reboot of 7912 IP phones


Check the CCM application logs and see what's the reason code for the unregistered device. It can be a network or a phone issue.

For Reason Codes definition check this link:

Also I would check that all the 7912s are running the latest firmware just in case!



Regards, Tere. If you find this post helpful, please rate! :)

Re: Continous reboot of 7912 IP phones


1st place where you can see what is happening - status messages on the phone(don't have 7912 near me but will have on Monday).

2nd Also you can try to verify whether everything is OK with network settings.

3rd try "show logging" command on cisco switch to which this phone is connected to see if the interface is not reseting.

4th Try to sniff traffic to see what the phone is requesting(or what it is not getting)

5th If you're using CCM 4.x - you can see phone resets in the event viewer in the Application logs.(or the reason which was before the phone starts to reset)

6th Try to reset to factory defaults:

Procedure A:

-Press **2. The phone displays "Do you want to reset all system settings to default values?"

-Press the Yes softkey.

•Procedure B:

-Press **#. If your phone displays "Enter Admin Password," enter your password and then press the Enter softkey. Make sure that an unlocked padlock icon appears in the upper-right corner of your LCD.

-Scroll to Erase Configuration.

-Press the Yes softkey and then press the Save softkey.