Allow Multiple Registrations for One Extension Number

Registering one extension number to multiple SIP endpoints allows the employees to handle calls on any devices. This topic describes how to set the maximum concurrent registrations for an extension.

Background information

For employees who work flexibly anywhere, they can register their extensions on multiple SIP endpoints, such as an IP phone in their office, a softphone on computer, or a SIP client on mobile phone. In this way, an incoming call can ring all endpoints at the same time, and users can handle calls at anywhere on any devices.


  1. Log in to PBX web portal, go to Extension and Trunk > Extension, edit the desired extension.
  2. In the Extension Information section, set the maximum endpoints allowed to register the extension in the IP Phone Concurrent Registrations field.
    In this example, set the concurrent registrations to 3.
    • The maximum number of concurrent registration is 3.
    • Concurrent Registration setting only limits the registration number of non-Linkus SIP endpoints. The registration number of Linkus clients is not counted.

  3. Click Save and Apply.


In addition to being registered on Linkus clients, the extension can also be registered on 3 other SIP endpoints.

When the extension receives a call, all the endpoints will ring. The extension user can handle the calls on any endpoint.

Note: By default, when the extension is busy in a call and a new call reaches, all the endpoints (Linkus and other SIP endpoints) can still ring.

To prevent other endpoints from receiving a new incoming call when an endpoint is busy, go to Extension and Trunk > Extension > Features > Call to enable All Busy Mode for Endpoints for the extension.