Busy Lamp Field (BLF) is a feature for many SIP desk phones that shows the line condition for other users on the same PBX (domain). The users are displayed as buttons on the device, depending on the number of feature buttons available on the model of phone.

Enable BLF

To use BLF, this will need to be enabled by selecting “Phones” then scrolling down to “Enable

Note: BLF is included for OnSIP customers on the Per Seat Metered Plan, though your OnSIP admin must still enable BLF for your PBX (organization) to use it. For customers on the Pay As You Go or Basic Plans, please refer to our pricing page.

Configure BLF

You will configure BLF individually for each phone via the OnSIP provisioning server. An instruction guide can be found in the knowledgebase article for setting up phones.

Technical Notes Updated October 2017 :  
* "Ringing" state has a three minutes timeout.
* "Committed" (On a call) has a one hour timeout.
* "Terminated" status has a 12 hour timeout.  Timeouts do not publish a status alert.