In CUCM version 10.X there's the settings "+E.164 alternate numbers and enterprise alternate numbers". Can these be used instead of configuring each DN as a E164/+E164 number? Preventing the required translation patterns needed for abbreviated dialing ? If so are there any Caveats? Or are these only for ILS/GDPR ?
I have been testing using the Enterprise Alternate Number. All my DID DNs are +E.164 numbers. For abbreviated dialing I always had translation patterns. With the EAN, I used the number mask to create the 5 digit EAN and added it to a local partition so that only that specific site could dial that 5 digit number. So far it works great. So much better than having all those translation patterns.
Where do you globalize the directory numbers from 4 digits to E.164, on the voice gateway or somewhere in CM?
That's what I suspected. As you pass the directory number from the gateway in 4 digit format that is likely why you get issue with the information passed to CUC. If you would have globalized the information from the PSTN service provider in the gateway on ingress, aka before sent to the CM, you should not have this issue.