[Asterisk-Users] Paging/Intercom (was: OT - SIP Auto-Answer for Cisco 7940/7960!!)

[Steven Critchfield]

On Sun, 2003-10-19 at 18:40, John Todd wrote:

> Looks useful, but requires essentially a second line to work as a 
> pager or intercom.  Not necessarily a bad thing, but as an an example 
> it would require a whole ATA-186 to just get one line and the 
> "paging" feature working, plus perhaps some additional wiring to work 
> that all into the power pair.  Also, it is unclear if that will work 
> at all, since there is no documentation on their website about how, 
> exactly, the "pager" or "intercom" features work.  It's completely 
> undiscussed at the nuts-and-bolts level (though they tell you what 
> buttons to push.)

Whats important to note, I think these do out of band negotiation on a
common wire pair. These phones usually are setup on the end of a set of
analog phones lines all wired the same. Basically instead of having a
intelligent switch front the phones, each phone communicates to each
other what it is doing. Since they need common wiring, a ATA186 wouldn't
help you here.

> I'm still waiting for a _good_ implementation of paging and intercom 
> for use with SIP.  Let's define "good" for an intercom/pager (i/p):
> 
> Mandatory:
>    - i/p can be activated while user is off hook (speakerphone or handset)
>    - deskset has local option for refusal of i/p while off-hook
>    - deskset has local option for refusal of i/p completely
>    - deskset has separate volume controls for i/p messages
>    - deskset plays announcement beep before intercom auto-answer
>    - password authenticated SIP messages for auto-answer i/p (i.e.: no 
> spam calls get through that aren't authenticated by a chosen upstream 
> proxy server)
> 
> optional:
>    - pager announcement audio via multicast (very, very optional)
> 
> JT
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-- 
Steven Critchfield <critch at basesys.com>