Here are some FAQ's from the LVS Site
Can the LVS 9000 ring multiple phones at the same time?
Yes. There are two methods by which the LVS 9000 can ring multiple phones simultaneously. One method allows for the
user to register multiple IP Phones with the same extension or DID. When a call comes into the SPA9000 destined for that
number the SPA9000 will ring all the registered phones assigned with that number. The second method employs the
Shared Line Appearance feature, whereby an extension is set-up that multiple clients share. When that extension receives
an incoming call, the phones that share that extension are rung. See below for additional information about how the
Shared Line Appearance feature works.
What is the Shared Line Appearance feature?
Shared Line Appearance (SLA) allows multiple stations to share an extension number and manage a call as a group. When
that extension receives an incoming call, the phones that share that extension will ring. When the call is answered by one
of the phones, all the other phones that share the line will still be able to access the state information of the call to know
who is talking on the shared line and to whom they are talking. If the call on the shared line is put on hold, all the phones
that share the line will be able to see that the call is on hold and they will have the opportunity to take the call off hold
and resume the conversation from their phone with a simple press of the shared line button.
The SLA is a valuable feature for teams who need to be able to dynamically handle calls without extensive manipulation
of the telephone. As well, the SLA feature is good for a manager and secretary relationship because the secretary's phone
can be set-up with a SLA of the manager's extension and therefore know at all times the state of the manager's extension.
This is valuable if the secretary routinely answers and screens calls arriving on the manager's line.