Multi-Site Customer with Extension Prefix and no ISP¶
In order to support Inter-Site calls without an Inter-Site Prefix (ISP), the first digit of site codes do not have match. The only requirement is that site codes should not conflict with extension or PSTN dialing. Customers use an extension prefix for intrasite calls.
Extension prefixes are useful when there is a conflict with PSTN Prefix or other Site Codes. They are also useful when you need to go from four- to five-digit dialing. This extension is still the last four digits of the E.164 number, but the last digit of an NXX code can be used as an extension prefix.
Multi-Site Customer with Extension Prefix and no ISP
| Dialing Format (A-Party) | Display Format (B-Party) | Notes | |
|---|---|---|---|
| Intra-Site Dialing |
|
|
Site Code = 255 Extension Prefix = 5 Number of extension digits = 4 Note: Even though the extension is dialed, the calling party number is displayed as a DN. Displaying the extension causes issues during Call Forwarding. |
| Inter-Site Dialing | Site Code + Extension (for example, 2551234) | Site Code + Extension | - |
| DN Format | Site Code + Extension (for example, 2551234) | - |
