Aastra Telecom 9143i Series User Manual

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Operational Features
41-001160-03, Rev 00, Releaes 2.4 
5-231
Configuring Operational Features
BLA Support for Message Waiting Indicator (MWI)
The IP Phones have an option for a Busy Line Appearance (BLA) configured line 
to send a SUBSCRIBE SIP message for a Message Waiting Indicator (MWI).
You can configure this feature using the configuration files or the Aastra Web UI.
Limitations
The following are limitations of the BLA Support for MWI feature:
The phone shows MWI for the first matching identity if more than one line 
with different user names has the same BLA account. 
If a normal line has the same user name as the BLA user of another line, the 
phone shows MWI only for the normal line.
Use the following procedure to configure BLA support for MWI.
Notes: 
1.
If you change the setting on this parameter, you must reboot the 
phone for it to take affect.
2.
Both the “sip explicit mwi subscription” and “sip mwi for bla 
account” parameters must be enabled in order for the MWI subscription 
for BLA to occur.
3.
The MWI re-subscription for the BLA account uses the value set for 
the "sip explicit mwi subscription period" parameter to re-subscribe.
4.
Whether or not the "sip mwi for bla account" parameter is enabled, 
the priority for displaying MWI does not change.
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