Having a consistent numbering scheme for your extensions allows for easier turn-up and easier reference points when troubleshooting.
For 3 digit extensions
| Number Range | Feature/Function |
| 100-199 | User Extensions |
| 200-299 | User Extensions |
| 300-399 | User Extensions |
| 400-499 | Call Queues |
| 500-599 | Call Queues |
| 600-699 | Conference Extensions |
| 700-799 | Call Parks |
| 800-899 | Auto Attendants |
| 900-999 | Auto Attendants |
For 4 digit extensions
| Number Range | Feature/Function |
| 1000-1999 | User Extensions |
| 2000-2999 | User Extensions |
| 3000-3999 | User Extensions |
| 4000-4999 | Call Queues |
| 5000-5999 | Call Queues |
| 6000-6999 | Conference Extensions |
| 7000-7999 | Call Parks |
| 8000-8999 | Auto Attendants |
| 9000-9999 | Auto Attendants |