You can define your own dialling plans in the Dialling plans area on the Web page: Settings - Telephony - Dialling Plans
You can specify the following Dialling Plans:
You can define a connection for specific phone numbers, which is always to be used to dial these numbers.
Define if the number is to be dialled with the area code.
If dialling plans overlap, the one with the greatest concordance will apply.
Example:
There is a dialling plan for the number "02" and the one for number "023". If you dial "0231.." the second plan will apply, if you dial "0208..." the first plan will apply.