An extension is a short number that identifies a user or device within your phone system. Extensions let callers and colleagues reach a specific person without dialing a full phone number. Every user who makes or receives calls in Voice needs an extension.
This article covers creating extensions, assigning them to users, configuring desk phones, and dialing by extension.
What an Extension Does
- Gives a user a short internal number (e.g., 101, 205) that others can dial directly.
- Links to the user's devices: web app, mobile softphone, and any physical SIP phones.
- Holds per-user settings like recording policy, voicemail greeting, and Do Not Disturb.
- Controls what number appears on outbound caller ID when the user makes calls.
Creating an Extension
Admins create and manage extensions from the Extensions panel:
- Go to Extensions and click Create Extension.
- Set the extension number (e.g., 101). Each number must be unique within your organization.
- Assign the extension to a user from your organization's user list.
- Optionally assign a direct phone number (DID) if this user should have their own inbound number in addition to the main number.
- Set the recording policy: Always, On-demand, or Never.
- Save.
Assigning a Voicemail Greeting
Each extension can have its own voicemail greeting. See Voicemail for instructions on recording or uploading a greeting.
Auto-Provisioning Desk Phones
Voice uses zero-touch provisioning for physical SIP phones. When you register a phone by MAC address, it downloads its configuration automatically the next time it reboots.
- Go to Devices and click Register Device.
- Enter the phone's MAC address (found on the label on the bottom of the phone).
- Assign the device to an extension.
- Save.
- Reboot the phone. It will connect to the provisioning server and configure itself with the correct SIP credentials, registrar, and line key settings.
If a phone boots and its MAC address is not registered, the request is logged under Platform Admin > Unknown Provisioning Requests so an admin can identify and register it.
Dialing by Extension
To call a colleague by extension:
- Open the dialpad in the web app or mobile app.
- Type the extension number (e.g., 101).
- Press Call.
Extension-to-extension calls stay within the platform and do not use PSTN minutes.
Extension Directory
The platform maintains a directory of extensions within your organization. When you type a name or partial number in the dialpad or search bar, matching extensions appear. This makes it easy to find a colleague without knowing their exact extension number.
Resetting an Extension PIN or Password
If a user needs their extension credentials reset:
- Go to Extensions and open the user's extension.
- Click Reset Password or Reset PIN (depending on the credential type).
- The user will receive instructions to set a new credential.
FAQ
How many extensions can I create? Extensions are limited by your organization's plan. Contact your MSP admin if you need to add more than your current plan allows.
Can one user have more than one extension? Typically each user has one extension. If your organization needs multiple lines for a single user (for example, a receptionist managing two lines), your MSP admin can configure shared-line groups for this scenario.
Can I reassign an extension number to a different user? Yes. Open the extension in the admin panel, change the assigned user, and save. Historical call records for that extension remain, but the extension will now belong to the new user.