Kudos to Daniel (and David's!) suggestion of using a SPA phone for overhead paging with the UC560! We had the amp tied into the FXS port on the UC560, but we still couldn't page both on the handsets and overhead even with a blast group. Also, we noticed that there was a bit of crackling and popping at the start of each page, and all the overhead speakers produced white noise. We bought a SPA504g (we wanted a true display) for $80 on ebay. Popped it open (use tiny flathead to defeat the "tamper-proof" screws in the SPA phone). Cut the speaker wires off the speaker inside and stuck them through one of the screw holes (no drilling needed). Put the unit back together. Used scotch-locks to tie the speaker wires to a pair of wires off of CAT5 that ran to the amp. Voila! Perfect. We actually had to turn the amp volume down. No popping, no crackling, no white noise. We taped the phone down (as you can see by our lovely picture, don't tape down the buttons though) and stuck it on the back wall of the IT closet where we could get to it if needed. Total cost: $82.00 for phone, scotch locks, piece of CAT5, two pieces of tape, and about 30 mins to modify and install. Downside: it uses one phone license.
Don't forget to assign an extension to the new phone and place it in your paging group!
