Matrix PRASAR UCS - Busy Lamp Field for Trunks

596 Matrix PRASAR UCS System Manual
Busy Lamp Field for Trunks
What is this?
On SIP extensions, PRASAR UCS supports the feature Busy Lamp Field (BLF) Subscription for Trunks, enabling SIP
extension users to monitor the status of desired trunks.
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Using BLF, SIP Extension users can monitor the status of different SIP Trunk.
To provide SIP extension users this feature, you must enable this feature on their SIP phones and configure the trunk to
be monitored on the BLF key of their SIP phones. The number of trunks that can be monitored will depend on the number
of BLF keys supported on the SIP Phones.
With BLF subscription and BLF key configured, whenever, there is a change in the state of the monitored trunk,
PRASAR UCS sends a NOTIFY message to the SIP Extension. The NOTIFY message contains the Call State. On
receiving the NOTIFY message, the SIP Extension updates the LED indication of the BLF key on the SIP phone.
The SIP extensions will indicate the following calls states for the outgoing and incoming calls on the monitored
trunks:
SIP phones may differ in the BLF indication (LED color and cadence, text message display) they provide
for the Call States. Refer to the manufacturer’s documentation for BLF Indication supported on the SIP
phones.
Outgoing Calls
Call State Description
Trying When an outgoing call is made through the monitored trunk.
Confirmed
When the external party answers the call and speech is established with the
extension user, that is, the call is matured.
Hold When the call on the trunk has been put on hold by the extension.
Available/Idle When the SIP Extension user disconnects the call.
Incoming Calls
Call State Description
Early When an indication is received from the Network that the external party is ringing.
Confirmed
When the incoming call is placed on the SIP Extension as the destination and
speech is established with the extension user, that is, the call is matured.
Hold When the call on the trunk has been put on hold by the SIP extension.
Available/Idle When the SIP Extension user disconnects the call