You will need to set your additional allowed extension as “200-299,300-399”. Since your main number is “623xxxxxxx” and you need 3 digit extension length, Default Allowed Extension will be “000-099”. So the system will not allow you to choose 0 for operator.
**FOLLOWUP QUESTION FROM PARTNER**
What is the significance of the “main number”? It looks like we can translate inbound numbers, so can we just arbitrarily assign a main number where the 3rd digit from the end is not 0 and then use 0 for operator?
The “Main Number” is equivalent to the “Front Desk / Operator’s” Number. When you create a user, by default the “External Caller ID” for that user will be set to the “Main Number”. The reason is, if the user does not have a DID, when a call is made from his/her phone the caller number will be sent as the main number. This way, the PSTN side can call back and reach the company’s main number. Even though you can translate the inbound number, the translation rule will not accept digits starting with “Operator” or “Feature” dial codes.
