You can change your outgoing caller ID, in the outbound rules, depending on the 3CX version you are using. If you want that to happen only when calling numbers with that area code, then you will have to have a rule specific to any number dialled using that area code.
It will have to be placed above any "catch-all" rule
i just add the rule of 514 number adding the 301 agent number but when i call 514****** then see different number on mobile instead of 301 see in attachment
Which version of 3CX are you using? That will depend on whether or not you can change the caller ID in the outbound rules.
Do you mean that the DID number (external caller ID), assigned to extension 301, is being sent?
See in the last line i write the rule so i call to the number 514..... to check from which number it receives its shows different number on mobile instead of 301
You are not understanding how outbound rules work.
Calls from field , you specify which extension the rule is applied to
Prefix, is added to the dialled number to format the dialled number correctly, so that it is in the correct format required by your sip provider. I.e you dial 1234 but the sip provider requires 99123 to dial the outbound number correctly , the prefix will be 99
The number presented to the dialled number, is controlled by your sip provider and normally is the main number unless you can mask the outbound number (if the sip provider allows this) and this is where the ‘outbound id’ comes in