How to Add BLF Keys to a Grandstream GXV3275

The Grandstream GXV3275 supports Multi-Purpose Keys (MPKs), which are virtual buttons you can place on the home screen. Configuring an MPK as a Busy Lamp Field (BLF) lets you see at a glance whether a colleague’s extension is on a call and call them with one tap. This guide walks through adding BLF keys directly on the phone.

Add a BLF Key on the GXV3275

1. On the idle screen, tap the MPK widget.
2. Tap Add New MPK (the first face icon on the left of the top menu).
3. Tap the icon a second time — it will now show a plus sign.
4. For Key Mode, choose Busy Lamp Field (BLF).
5. Fill in the Name and the Extension number of the contact you want to monitor.
6. Tap OK to save.

The new BLF virtual key will appear both in the MPK application and on the MPK widget on the idle screen.

Configure BLF Keys From the Web GUI

You can also manage BLF virtual keys from the GXV3275 web interface. Sign in to the phone’s web GUI and go to Advanced Settings > MPK LCD Settings. The web GUI is more convenient when you are setting up several BLF keys at once or copying configuration across multiple phones.

Grandstream BLF FAQ

What does a BLF key actually do?

A BLF (Busy Lamp Field) key shows the live status of another extension on your phone. The key lights up when the extension is in use and changes colour while it is ringing. Tapping the key dials the extension directly.

Where do I find the IP address to log in to the GXV3275 web GUI?

On the phone, open Settings > Status > Network Status. Type the IPv4 address into a browser on the same network to open the web GUI. The default username and password are configured by your administrator.

Can I add a BLF for an external phone number?

BLF only works for extensions registered on the same EMAK Telecom phone system. For external numbers, use a Speed Dial MPK instead — the steps are the same, but you set Key Mode to Speed Dial and enter the full phone number.

Why is my new BLF key not lighting up?

If the BLF key never changes state, double-check that the extension number is correct and that the extension is registered on the same phone system as your GXV3275. If the issue persists, contact EMAK Telecom support — we may need to enable BLF subscriptions for your account.