VoIP with Analog PA Systems and Visual Alerts?

An anonymous reader asks: "We have an Asterisk/SIP based VoIP system at work, and I've been tasked with adding some features. First, we need to be able to patch it into our analog PA system at several office locations. I've managed to hack together a polycom phone set to auto-answer, and a custom cable from the handset to plug into the PA. This works well enough, but the phone really isn't designed for it, and I find that it just isn't reliable. What I need, and haven't been able to find, is a simple SIP enabled device that will auto-answer, and has line-out that I can feed to the PA. That way, if a user calls one of several numbers, they get tied into the associated PA system, or maybe even all PA systems at once. The next piece of the puzzle is a visual alert so that when a SIP phone is ringing, a light flashes. This will allow people in a loud environment to still know the phone in the office is ringing." Any ideas as to how this could be done? "Ideally this would be just another SIP device that I could have Asterisk dial the same time the office phone gets dialed. The analog version of these is easy to come by, but I haven't been able to find a networked SIP version anywhere.

I'm not above building my own if their are some basic SIP device schematics out there, but I'd rather find a commercial solution and be done with it. Any help will be greatly appreciated."