How to configure Busy Lamp Field (BLF) on snom phones

Busy Lamp field (BLFBusy Lamp Field - A set of indicators that monitor the current state (online, offline, busy, on a call) of a phone extension.) feature allows users to monitor several other extensions. Sometimes the term Direct Station Selection is used for the same functionality. State of the monitored extensions is usually indicated by a series of LED lights with buttons.

  • Idle state – LED is off.
  • Ringing state – LED is blinking.
  • Busy or Connected state – LED is on.

The Call Pickup function is usually configured together with BLF allowing, for example, a receptionist to pickup ringing calls with a press of a single button.

Operator configuration

Busy Lamp Field

There is no configuration needed to make BLF work.

Call Pickup

Enable the Call Pickup feature and configure an extension (e.g. "**”). When dialing **10 while extension 10 is ringing, the call will be redirected to your phone.

Phone configuration

Follow these steps on snom 360 (firmware 8.4.18) and snom 820 (firmware 8.4.32).

  1. Open phone administration in your browser (eg.
  2. Make sure that the phone is running firmware version 8.
  3. View screen Setup > Function Keys.

  1. Configure BLF function on the buttons P1...Px and set:
  1. First field to Active
  2. Second field to BLF
  3. Third field to <sip:extension@ipAddress;user=phone>|callPickup. Here
  • extension is the monitored extension (e.g. 10).
  • ipAddress is the IP address of Operator (e.g.
  • callPickup is the Call Pickup extension (optional).

For example, <sip:10@;user=phone>|**. In this example, ** signifies that extension 10 doesn't use the Call Pickup feature.

  1. Don't forget to save the configuration.

Call Parking

To park a call, first place the caller on hold. Then dial to a designated parking slot (e.g. *53). If you have configured BLF keys to monitor parking slots, you can simply press the key which is monitoring the parking slot (e.g. *53). After you hear the announcement you will then hear the hold music. You can then press the transfer button to join the caller into the parking slot. The caller is then parked, and you can hang up the call.