[on-asterisk] Public Address interface device recommendation.

[Kevin Anderson]

Good afternoon.
I am moving a school to voip.  They currently have a PA system that I can tie 
into using either a 3.5mm headphone jack, or RCA cables.
Is there a device that can autoanswer a SIP call, and output voice in a way 
that I can plug into the PA system?  I'd rather not hack something together if 
there's a single unified device I can use to meet the need.
ThanksKev.