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 particular model of phone (see chart below).

Enable BLF

To use BLF, you must enable it for your PBX (organization) in the "Account" tab of the admin portal. If your account has more than one PBX (organization), please ensure the correct one is selected in the "Active PBX" (top left-most) drop down.

Once on the "Account" page, click on the link for "Enable Busy Lamp Field" in the PBX Settings box. After reviewing the Busy Lamp Field information box, click on "Confirm."

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.

Updated October 2019

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  Timeouts do not publish a status alert.