Extension Schemas

Information about Extension Schemas

The following information is simply an example of an extension numbering schema.  The advantages of adopting a schema for your company will help when you support multiple clients a day, to see the same organizational setup across all of your clients domains. 

Schema Considerations
NOTE:  Keep in mind, you should use a 3 or 4 digit extension.   Avoid the reserved number spaces like 411, 611, 911, 933 and special functions.

Organizationally speaking, you may want to consider if the client has more than one (1) location.  When you visit a hotel, or a hospital, typically the first number represents what floor you need, followed by a room number.   You could consider this same type of numbering schema to create your extensions 1000's for the first location, and 2000's for the 2nd building or location.  

Example Schemas

100 - 199 Users extensions 
200 - 299 More available extension range
300 - 399 Routing Users / Ring Groups / General Voice Mail etc.
400 - 499 Conference Bridge extensions
(Except for 411)
500 - 599 Auto Attendants
600 - 699 Call Queues
(Except for 611) 
700 - 799 Reserved Space for Parking Features
800 - 899 Available extension range
1000 - 1999 Users extensions in Building 1
2000 - 2999 Users extensions in Building 2


See this article for other Reserved Number spaces.