The minimum number of UDP ports to open depending on the PBX model:
| Model | Calls | Ports |
| WGW08 | 4 | 572 |
| WGW16 | 8 | 687 |
| WGW40 | 15 | 1287 |
| WGW90 | 30 | 1716 |
| WGW250 | 120 | 3432 |
| WGW500 | 150 | 4290 |
| WGW1000 | 300 | 8590 |
| WGW5000 | 600 | 17160 |
The formula is the following one: “(M x Number of calls) + 10%”, where M is:
- 130 for PBX supporting up to 7 concurrent calls
- 78 for PBX supporting up to 23 concurrent calls
- 50 for PBX supporting up to 45 concurrent calls
- 26 for PBX supporting more than 45 concurrent calls