Asterisk. Dialing a city number is not in the federal format?

Question

Asterisk

Good evening!
Trying to master Elastix. Faced the following question, the provider dials phones only in the federal format: 7 XXX XXX XX XX. My knowledge was enough to make a set not through 7, but through the usual 8ku.
(prepand) + (prefix) | match pattern
8 + 7 | X.
But it is not clear what to do with calls within the city where you do not need to enter the area code and where to register it in the same trunk or create another one with the same parameters, but with a different dialing rule?

Answer 1

The area code does not need to be entered to the caller, but you catch for example _XXXXXXX in the extension and make a call to number 7code {EXTEN}
I don’t know how to do it in Elastix, I know in the classic lamp asterisk.

Answer 2

look, if memory does not change prepend 7812
for Peter , leave the prefix empty in the XXXXXXX pattern , dial 1234567 - he calls 78121234567 if, for example, put the prefix 4, then you will need to dial 41234567 I may be wrong