[Asterisk-Users] Paging & Intercom

[willy at yponeinc.com]

Hi all!
Having stuck my neck out and going for [*] for our new 
sales office, (instead of upgrading a 
Meridian-Nortel key system), one of the main concerns 
remains the support (or lack thereof) of paging / 
intercom functionality.  Maybe I am just missing somthing 
elementary?  Here goes:
After perusing the list archives, I am more & more concerned
about the 'paging' 'voice call' 'intercom' scenario.

Quoted below is a message from John Todd (sometime last
year) on the list:
<quote>
This is not an explicit answer to all of your questions,
but...

1) There is currently no intercom functionality supported by
Asterisk as an "in-band" method of communicating with
phones. There is the ability to make audio on a phone call
appear out of the sound-out port on a soundcard, which may
be what you're after if you have a PA system of some sort.

2) You can do everything you're looking for with Asterisk.
Spend a bit of money on some hardphones (Cisco ATA-186 is my
personal bias, since they have 2 lines and they're cheap)
and get an X100P analog adapter. Everything you've mentioned
can be demo'ed with that configuraion.

JT
</quote>

Let's see if I got this right:
(a) single line SIP phones (e.g. GS-BT100) not likely to
provide "auto answer" on demand, i.e. allow a 'page' to come
through
(b) multi line SIP phones: configure an extension for "auto
answer".  [*] may support all-page by sending voice to all
non-busy phones at the same time
(c) use ATA-186 - or similar - adapter, and inexpensive
ANALOG (2 line?) phone to provide the intercom / pageing
functionality

For a deployment where there is a relatively large number of
phones, the cost-per-phone evidently becomes a principal
driver. 

Here's the user classes:
(1) regular user:  inexpensive GS BT100 may work.  
(2) power user / manager
(3) shared phones in public areas: i.e. kitchen, computer
room
(4) attendant

Using an old-style paging system is out of the question. 
Paging must be supported through the hard phones.
Any ideas?