[cisco-voip] how to allow alternate routes for unregistered phones

[Kelemen Zoltan]

Hi!

I'm trying to migrate some phones from a PBX to a CCM system. The CCM 
currently has a route pattern towards the PBX and the migrated phones 
will have extensions from the same range.

Since there are a lot of phones and some administrative hurdles as well, 
I can't just move all the phones at once. What I wanted to do, was to 
register the IP phones in the CallManager, keep the route pattern, and 
deploy the phones as I can.

I just supposed, that a phone, as long as it's not registered with the 
CallManager won't "take over" the call to it's line number and allow the 
call to go out on the route pattern. Only it isn't working like that. Is 
there any setting I can change to make it work like I expect it to?

Ex:

Route pattern to 4XX goes out to gateway.
451 is registered to CCM, 452 is configured but in "not registered" 
state, 453 isn't added to CCM at all.

What I expect to happen:
Calling 451 rings out on IP phone, while calling 452 and 453 would go 
out to the PBX and ring there, if applicable.

What happens instead:
451 rings, 452 gives busy, 453 goes to PBX.

Dialed Number Analyzer shows an alternate match for 452, but that's it.

(I'm currently testing this on CCM4.2, with a IP Communicator, but I 
don't really think that's relevant)

thanks,
  Zoltan