Yealink T27G

Advanced Features
451
State Indicator of Remote Line
The state indicator of the monitored line on BLF/BLF List key varies by phone models.
The following table shows the LED/icons indicator associated with the line you are monitoring.
LED Status
Icons
Description
T48S/T48G
T46S/T46G/T29G
T54S/T52S
Solid green
Monitored line is
idle.
Fast-flashing
red
(Flashing)
Monitored line is
ringing.
(Flashing)
Monitored line is
dialing.
Solid red
Monitored line is
busy or in a call.
Slow-flashing
red
Monitored line
places a call on hold.
A call is parked to
the monitored line.
Off
Monitored line
registers failed or
does not exist.
BLF/BLF List Subscription
Yealink IP phones support BLF using a SUBSCRIBE/NOTIFY mechanism as specified in RFC 3265.
BLF Subscription
When you configure the IP phone to monitor a specific line, the IP phone sends a SUBSCRIBE request
with Request-URI containing the monitor line URI to the server, and then receives a NOTIFY request. The
NOTIFY message contains XML body with status of the specific monitored line.
The following example shows a NOTIFY message for a BLF line “012”:
<?xml version="1.0"?>
<dialog-info xmlns="urn:ietf:params:xml:ns:dialog-info" version="1" state="full"
entity="sip:012@10.20.10.42:5060">