How to Set Up BLF Keys on Your Yealink Phone
A BLF (Busy Lamp Field) key lights up to show whether a colleague's extension is busy, ringing or free — and lets you transfer a call to them with a single press. It's one of the most useful features for a reception desk or small team.
Applies to: Yealink T33G, Yealink T54W, Yealink SIP-T85W, Yealink SIP-T87W
5 steps to get it done
Open the DSS key menu
On the phone, go to Menu > Features > DSS Keys (the exact wording may vary slightly by model).
Select the key you want to program
Choose an available programmable key on the phone — usually one of the line keys down the side of the screen.
Set the key type to BLF
When prompted for the key type, choose BLF.
Enter the extension to monitor
Enter the full extension number of the colleague or line you want to monitor.
Save and test
Save the configuration. The key should now light up to show that extension's status, and pressing it while on a call will let you transfer directly to them.
Tips:
- BLF keys can also be configured through the phone's web interface if you prefer setting up several at once, or WiseCloud can configure them for you as part of setup.
- This is especially useful at reception desks where staff need to see at a glance who's available before transferring a call.
Quick answers
What does BLF stand for?
Busy Lamp Field — a light on the phone that shows whether another extension is busy, ringing or free.
Can WiseCloud set up BLF keys for us?
Yes — we can configure BLF keys as part of your cloud phone system setup, so your reception desk is ready to go from day one.
Need a hand with setup?
WiseCloud can configure your handsets, headsets and network gear for you as part of installation — no troubleshooting required.