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Extensions for external numbers

About extensions for external numbers

Your organisation can set up extension numbers for people you contact frequently in other organisations, such as clients, suppliers, partners or subcontractors. These contacts appear in your company's main phone book and can be called by dialling their virtual extension number rather than their full phone number.

Diagram showing a user calling an external user with an extension

If you have the extensions for external numbers service assigned, you can dial contacts using the virtual extension rather than the full phone number.

You can also forward calls to virtual extension numbers.

Caller ID and extensions for external numbers

An extension for an external number has its own caller ID, which is displayed during calls instead of the person's external caller ID. The contact's external caller ID is used in emails notifications, voicemail messages and call logs.

For example, in the example above, the caller ID name for Zhao's extension may be set to XYZ Sales. When Zhao calls Fulanah, the caller ID number shows as 44 and the caller ID name shows XYZ Sales. In the call log, however, the calling number is recorded as (222) 4321.

Setting up extensions for external numbers

You can set up extensions for external numbers on an individual basis or for a range of numbers if you want to match extensions to a set of contiguous phone numbers.

Extensions for external numbers are set up for a site and can only be used by the users at that site. The extension numbers must be unique in your organisation. Contact your enterprise administrator if you don't know the range of numbers you should use for your site.


Virtual extension numbers can't be used by virtual users, such as hunt groups, auto-attendants or call centres.

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