Operational Features
5-114 41-001160-00, Release 2.1, Rev 04
IP Phone Administrator Guide
Operational IP Phone Features
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 the 55i, 57i, and 57i CT, 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 the 53i, 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.
Note: The BLF setting is applicable to the Asterisk server only.
Note: You can configure a maximum of 50 BLFs on the 536M and 560M
Expansion Modules.