Asterisk How to call in your city without dialing the area code?

Question

Asterisk

Don't kick too hard, just learning.
Asterisk + CentOS server deployed.
Connected sip-provider. In this case, calls in your city have to be made by dialing 7 (area code) (number).
To call an external number, the following was written in the dialplan:

exten => _XXX.,1,Dial(SIP/${EXTEN}@digits)

The numbers are seven digits. I guess it should be something like this?:

exten => _XXXXXXX,1,Dial(SIP/$7342{EXTEN}@digits)

In general, neither I nor Google know how to prescribe parameters in extensions.conf in a bare Aster so that I do not dial a prefix when making calls in my city.

Answer 1

exten => _XXXXXXX,1,Dial(SIP/7342${EXTEN}@транк)