# Monitor Extension Status by BLF Key on Fanvil IP Phone

A Busy Lamp Field (BLF) key lets one phone keep an eye on another extension. Once assigned, the key's LED reflects that extension's live call and Do Not Disturb (DND) state, and a single press dials the line or answers its ringing calls. This walkthrough uses a Fanvil X6U-V2 running firmware 2.12.1 as the reference model; the portal steps are the same for other auto-provisioned Fanvil handsets.

## Before you begin

The Fanvil phone must already be provisioned through Cloud Voice Auto Provisioning (the PBX pushes each phone's settings to it automatically, rather than you typing them into the handset) and have an extension assigned to it. If that isn't set up yet, work through [Auto Provision Fanvil IP Phone with Cloud Voice](/pbx/ip-phone-configuration-guide/auto-provision-fanvil-ip-phone-with-cloud-voice-cloud/) first.

## Step 1: Define a BLF function key on the extension

1. Sign in to the PBX web portal and open **Extension and Trunk > Extension**, then edit the extension that belongs to the Fanvil phone.
2. Open the **Function Keys** tab.
3. Set up a key to track another extension. The example below monitors extension 1004.

   ![BLF function key configured to monitor extension 1004 on the extension's Function Keys tab](/images/pbx/set-blf-to-monitor-ext-on-fanvil.png)

   - **Type**: Choose **BLF**.
   - **Value**: Pick the extension you want to monitor from the drop-down list.
   - **Label**: Optional text shown next to the key on the phone screen.

   :::tip
   Give the key a short, recognizable **Label**, such as the person's name or extension number. It appears on the phone screen, so the user can tell at a glance which line the key is watching.
   :::
4. Click **Save**.

## Step 2: Push the change to the phone

Saving in Step 1 stores the BLF key in the extension's configuration on the PBX. The key only shows up on the physical handset after you reprovision the phone.

:::caution
Reprovisioning reloads the phone's full configuration from the PBX, so do it when the handset is not on an active call. The phone also needs to be online and registered to receive the update.
:::

1. Go to **Auto Provisioning > Phones** and click the refresh icon ![Reprovision icon](/images/pbx/refresh.png) next to the phone you just edited.

   ![Reprovision prompt shown after clicking the refresh icon beside a Fanvil phone](/images/pbx/reprovision-fanvil-phone.png)

2. When prompted to reprovision the phone, click **OK**.

## Result

The BLF key's LED now tracks the monitored extension (extension 1004 in this example) in real time:

- **Solid green**: The extension is idle.
- **Solid red**: The extension is placing or is on a call.
- **Solid yellow**: The extension is in DND.
- **Flashing red**: The extension is ringing.
- **LED off**: The extension is unregistered or has been removed from the system.

:::note
Some Fanvil models don't distinguish DND with its own color and instead show DND as **solid red**. Check with your Fanvil phone provider for the models and firmware versions that support a separate DND indication.
:::

Pressing the BLF key lets you:

- Call the monitored extension directly.
- Answer an incoming call ringing on the monitored extension.

:::note
Answering another extension's calls requires the Extension Pickup feature code to be turned on. You'll find it under **Call Features > Feature Code > Call Pickup > Extension Pickup**.
:::