Aastra 9143i Series Administrator's Manual page 523

For ININ Server
When configuring the BLA feature on an ININ server, the value set for the sip
lineN bla number parameter shall be the same value set for the sip lineN user
name parameter without the incremented digit added to the phone #. For example,
if the sip lineN user name for the first phone is 10101, and the sip lineN user name
for the second phone is 10102, etc., you would configure BLA on a per-line basis
for the ININ server as follows:
(# for phone 1 with appearance of phone 3)
sip line1 mode: 3
sip line1 user name: 10101 sip line1 bla number: 1010
(# for phone 2 with appearance of phone 3)
sip line1 mode: 3
sip line1 user name: 10102
sip line1 bla number: 1010
(# for phone 3)
sip line1 mode: 3
sip line1 user name: 1010
sip line1 bla number: 1010
Use the following procedures to configure BLA on the IP phone.
Configuring Global BLA
Configuration Files
For specific global parameters you can set in the configuration files, see Appendix A, the section,
"SIP Basic, Global Settings"
Configuring Per-Line BLA
Configuration Files
For specific per-line parameters you can set in the configuration files, see Appendix A, the section,
"SIP Basic, Per-Line Settings"
41-001160-03, Rev 00, Releaes 2.4
Note: The original phone number which has the bridged line appearance
on other phones, will have the "sip lineN user name" parameter the same
as the "sip lineN bla number" (1010 in the above example on Phone 3).
on page A-67.
on page A-76.
Configuring Operational Features
Operational Features
5-225