Yealink SIP-T4U Series

Advanced Features
436
LED Status
Icons
Description
T48U/T48S/T48G T46U/T46S/T46G/T29G T57W/T54W
Solid green The monitored line is idle.
Fast-flashing
red
(Flashing)
(Flashing on
T57W)
The monitored line is ringing.
(Flashing)
(Flashing on
T57W)
The monitored line is dialing.
Solid red
The monitored line is busy or in a
call.
Slowly-flashing
red
The monitored line places a call on
hold.
A call is parked to the monitored
line.
Off
The monitored line fails to register or
does not exist.
BLF/BLF List Subscription
Yealink 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 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 con-
tains an XML body with the 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-
y="sip:012@10.20.10.42:5060">
<dialog id="0000" > <state > terminated</state > </dialog >
</dialog-info>
BLF List Subscription
When you configure the IP phone to monitor a list of specific remote lines, the phone sends a SUBSCRIBE request
with Request-URI containing the BLF List URI, and then receives a NOTIFY request. The NOTIFY message con-
tains an XML body with the status of each monitor line.
The following example shows a NOTIFY message for a BLF List, the BLF List contains 4605 and 4607:
<?xml version="1.0" <?xml version="1.0"?>
<list xmlns="urn:ietf:params:xml:ns:rlmi" xmlns="urn:ietf:params:xml:ns:rlmi" version="0" fullState="true">
<resource uri="sip:4605@pbx.yealink.com">
<name > 4605 Yealink</name>
<instance id="JQZxud2qeo" state="active" cid="8y35ri@broadworks"/>
</resource>