Problems with switching 7960 IP Phones between CUCM servers

[thowes]

I have a CUCM setup with several different hard drives (each with a different version of CUCM) that I swap between as the occasion calls for it.  I only have 5 IP Phones (7960 model) so I do a factory reset when I need to connect them with a different version of CUCM.  I also have a UC520 that I occasionally use the phones with.  Right now I am having problems connecting my phones to my CUCM 6.1 system.  There are no devices set up but I have autoregistration turned on so from what I understand that shouldn't matter.  I am also not over or near my license limits.  None of my phones seems to want to register with the CUCM 6.1 system, even after doing a factory reset and then pointing them directly to the IP address of the server.

Since these phones had previously been connected to a CUCM 8.0 and a UC520 (not sure what the version is but we have only had that system for about a year) is it possible that the phones are just unable to downgrade their firmware?  Has anybody seen this type of issue before?

[paolo bevilacqua]

There is no need to delete firmware or factory reset each time. The latest works with all.

Recovery is more easy done with the uc520 and checking "debug tftp events".

[thowes]

I don't ever have any problems connecting to the UC520, just to the CUCM 6.1.  I plugged all of the phones directly into the UC520 earlier this morning and none of them had any problems connecting to that, but when I try to plug them directly into the CUCM 6.1 (or when I plug them into the wall and connect through the network) they don't want to connect.

[Rob Huffman · Accepted solution]

Hi there,

It's quite possible that the Phone Firmware was upgraded to a

"signed" version when connected to CUCM 8.x and won't load a

"non-signed" version that the CUCM 6.x is trying to use. I would determine

what loads are default on the 8.x box and load the same version on your 6.x

servers.

Cheers!

Rob

[thowes]

Turns out that this wasn't a CUCM issue at all.  I had all of my phones connected to a linksys switch and then to the wall, and for some reason they were picking up config settings from that switch.  Quite strange, but my IT dept was able to figure it out.  Thanks for your help, though, Rob.  It was probably a good thing to update the phone firmware for my 6.1 box anyway!