BLF – Busy Lamp Field

Learn more about the Busy Lamp Field, what it is and how to set it up.

The Busy Lamp Field (BLF) feature enables the IP phone to monitor specific remote lines for state changes on the phone. For example, you can configure a BLF key on the phone to monitor the status of another phone’s line (busy or idle). The BLF key LED glows red when the other phone’s line is in use (busy).

BLF List feature enables you to monitor a list of users defined by your system administrator. For example, your system administrator has enabled the BLF List feature and created a BLF List URL (for example, with user1 and user2 in the list on the server. After configuration, the BLF List keys on the IP phone can present the status of user1 and user2, and the respective key LEDs or icons will illuminate either flashing or solid depending on the status of monitored lines.

Note: It is applicable to all phones except T30P/T30/T19(P) E2/CP920 IP phone. *As seen on Yealink Support links and manuals.*

You can use the BLF key to do the following:

  1. Place a call to the monitored user
  2. Pick up an incoming call of the monitored use
  3. Transfer a call to the monitored user (The phone handles the active call differently depending on the configuration of Transfer Mode via DSS key)
  4. Park a call to or retrieve a parked call from the monitored user
  5. Barge in a conversation and set up a conference call (only for BLF List)

Support Links for BLF: