Seize a Trunk to Call Out by BLF Key

This topic describes how to configure a BLF key on your IP phone via Auto Provisioning to monitor the PBX trunk, and press the BLF key to quickly place an outbound call through the monitored trunk.

Prerequisites

  • If you want to seize a trunk to call out by BLF key, make sure the extension assigned to the provisioned phone has the permission to use the monitored trunk for outbound calls.
  • If multiple extensions are registered to the phone, ensure the SIP line set as the function key line is active on the phone, and identify the extension assigned to the SIP line for subsequent configuration (Path: Auto Provisioning > Phones > > Assign Extension).
    Note:

    You can check on the phone whether the LED for the target SIP line is steady‑on (a steady‑on LED means the line is active). If not, press the corresponding line key to switch to the target line.

Procedure

  1. Log in to PBX web portal, go to Extension and Trunk > Extension, edit the desired extension.
  2. Click the Function Keys tab.
  3. Configure a function key to monitor the status of a trunk.

    The following figure shows a configuration example of monitoring the trunk peer-trunk-66.41.

    • Type: Select BLF.
    • Value: Enter the name of the trunk to be monitored. In this example, enter peer-trunk-66.41.
    • Label: Optional. Enter a value, which will be displayed on the phone screen.
  4. Click Save.

Result

  • The BLF key shows the real-time status of the monitored trunk:
    • Green BLF LED: The trunk is being monitored, and the status is idle.
    • Red BLF LED: The trunk is busy.
    • BLF LED off: The BLF key configuration failed.

  • Press the BLF key to seize the trunk, you will get a dial tone, then dial the number that you want to call.