AASTRA 6700i series, 9143, 9480i, 9480i CT SIP Administrator Guide EN - Manual (Page 435)

5-158 41-001343-01 Rev 03, Release 3.2.2
Busy Lamp Field (BLF)
The BLF feature on the IP phones allows a specific extension to be monitored for state changes.
BLF monitors the status (busy or idle) of extensions on the IP phone.
Example
A Supervisor configures BLFs on his phone for monitoring the status of a worker’s phone use
(busy or idle). When the worker picks up his phone to make a call, a busy indicator on the
Supervisor’s phone shows that the worker’s phone is in use and busy.
BLF Setting (For use with Asterisk)
On 8 and 11-Line LCD phones, the busy and idle indicators show on the IP phone screen display
next to the softkey or programmable key configured for BLF functionality. When the monitored
user is idle, an icon with the handset on-hook shows next to the BLF softkey or programmable
key. When the monitored user is on an active call, a small telephone icon is shown with the
handset off-hook.
On 3-Line LCD phones, the LED lights next to each BLF programmable key illuminate steady
to indicate the monitored line is off-hook or unregistered. The LED goes off when the line is
idle.
You can configure a BLF key on the IP Phones using the configuration files or the Aastra Web
UI.
Note: The BLF setting is applicable to the Asterisk server only.
Note: You can configure a maximum of 50 BLFs on the M670i and
M675i Expansion Modules.