AASTRA 6700i series, 9143, 9480i, 9480i CT SIP Administrator Guide EN - Manual (Page 480)

41-001343-01 Rev 03, Release 3.2.2 5-203
Bridged Line Appearance (BLA)
A SIP bridge line appearance (BLA) on the IP phones allows multiple devices to share a single
directory address (DA).
For example, people working at a technical support department could be located in different
places. If their desktop phones are configured for BLA DA, when customer calls come in, all the
phones with the BLA DA would ring but the call can only be answered by one of them.
Once the call is answered, the rest of the phones reflect the status of the call. If the call was put on
"hold" by the original recipient, any one from the group can pick up the call.
You can apply BLA on the IP phones as follows:
• As a single BLA group - One BLA DA is shared among multiple phones. Only one phone at
a time can pick up an incoming call or initiate an outgoing call on the BLA DA. All phones
reflect the usage of the BLA DA. If the call is put on "hold", any one from the group can pick
up the "held" call.
• As a multiple BLA group - On one single phone, multiple BLA DA can be associated with
different line appearances. Every BLA DA is independent from each other and follows the
same rules as "a single BLA group".
• As multiple instances of a BLA DA - A "x-line-id" parameter was defined in
draft-anil-sipping-bla-02.txt to present the incoming call to or place an outgoing call on the
specified line appearance instance. The parameter is carried in "Alert-Info" header field over
the request-URI (INVITE e.g.) or in the NOTIFY messages to report the status of a dialog.
BLA DA can be configured on a global basis or on a per-line basis on the IP phones using the
Aastra Web UI or the configuration files.
The following table shows the number of lines that can be set to BLA for each model phone.
Note: This feature is dependent on the IP telephony system to which the
IP phone is registered and according to draft-anil-sipping-bla-02.txt.
IP Phone Model
Possible # of BLA
Lines
9143i 9
9480i 9
9480i CT 9
6730i 6
6731i 6
6735i 9
6737i 9
6739i
9
6753i 9
6755i 9
6757i 9
6757i CT 9