Article ID:3807679

List of Implementation Extension Schemes

Written By Jexter Reyes (Administrator)

Updated at May 11th, 2026

Symptoms

  • VIP Implementation - Extension Schemes
     

Procedure

IMPORTANT: Customers usually have an extension scheme in place. When building out a domain, we should strive to stick with the original scheme as much as possible.

 

Use

When creating a new domain, we should use the following extension schemes for users:

  • 100-999
  • 1000-8999
  • 10000-199999
  • 100000-199999
 
 

Don't Use

NOTE: x11 numbers are set to only show the outbound caller ID on X11 numbers. However, they must also display the outbound CID and PSAP or location information.

 

These extension numbers should not be used for user extensions:

  • 111
  • 211
  • 311
  • 411
  • 511
  • 611
  • 711
  • 811
  • 833
  • 911
  • 933
  • 999
  • 5000 & 5001
  • 9000-9999
 
 

 


When building call flows, use the following guidelines:

Call Queues, Auto Attendants, and Conference lines Extensions 8500-8999
Call Parks Extensions 9000-9999
Paging units (Snom, Cyberdata) Extensions 7777 & 8888 are the most common

IMPORTANT: When adding devices, put them in one server for the entire account: USW, USC, or USE.

 

Choose the closest server to the Main location if there are multiple locations. Geo IP routing will automatically go into place when calls are placed. Keeping devices all tied to the same server is important to make sure all features are working across the account. 

The system in the backend will auto-balance calls, features, and presence without the need to assign servers to devices.
 

Escalation Information

Escalation Information: SD1

If you need additional assistance, contact Crexendo Support at 855-211-2255 or email us at support@crexendo.com

 

Change Log

Date Description
May 12, 2026 Article migrated and revamped