[Asterisk-Users] Cisco 7940 Phones as paging system?

[Rich Adamson]

> I have been searching for an answer to a question that a customer asked 
> me and I have only found a few older answers.  So, wanting to find out 
> if anyone has any experience with this issue and can help provide me 
> with some advice.
> 
> I have a customer which is strongly interested in using Asterisk as a 
> PBX.  One of the core requirements, however, is that the system MUST be 
> able to support intercom/paging.  Having searched the archives, it 
> appears that this question was asked about 6 months ago, and the answer 
> was that the Cisco phones support this using SCCP and having one line 
> set to auto-answer, but at the time this was not supported in the SIP 
> image.  Is this still the case?
> 
> Although I know that SIP is the preferred protocol for connecting these 
> phones with Asterisk, how stable/reliable are the skinny channels?  Is 
> there any reason I should be rethinking this solution?

Apparently your search didn't find several other postings on the subject.

The cisco v6.x sip releases also include the ability to "auto-answer" a
call (required for phone paging), however some folks tend to suggest that
is a security problem as anyone can call that autoanswer extn number
and listen in on whatever is going on around the phone. There is no
beep or other indication the phone/microphone is open.

If your customer is looking for overhead (as in PA) paging, there are lots
of postings relative to add-on hardware, etc, to do that. Use of the 
sound card within the * box has historically been hit/miss as not all
sound cards are supported, etc.

Rich