I did an installation of CUCM 7 recently and had some problem with the numbering and DDI. The company where I deployed the CUCM already had a PBX with extension which they had to change due to corporate numbering plan. So on the CUCM we implemented the new extensions, but they wanted the old DDI numbers to remain the same - DDI number X which was directed to person Y with ext W on old PBX had to go to the same person Y with extension Z on CUCM. The problem is that ext W and ext Z had no connection between. One could be 4356 and the other 3898. So I couldn't do any translations/transformations to reach the desired result.
I didn't found any better way so I resolved the incoming calls with an extension in the middle, so call goes to some modification of the old extension W and then by Forward All is transfered to the new extension Z.
But I cant't solve the outgoing presentation of the Caller number. I've set up they to present with only one number, but I'm still trying to find a sloution everybody to present with the rigth DDI No (the one that is directed towards that extension).
The only acceptible solution I found was to use the External Phone Number Mask field, but the problem with this is that it shows at the phone screen and that is not acceptible for the company. They want the users to see their new extensions.
So I'm looking for help to resolve this in two ways:
- either do some kind of translation/transformation of the caller No on the way out without some big performace impact on the CUCM (we are talking about ~200 extensions)
- use the External Phone Number Mask but find some way to not show it on the screen or completely hide the field where the ext/External Phone Number Mask is shown on the phone.