I agree. The FIRST thing you need to do is connect your butt set and see what comes out of the page port!

I see a remote possibility that the power supply may be at fault if the ring is really loud and it pulls down the power supply voltage. Paging isn't that loud or continuous. So if you have ROP correctly on the page port I would look at the power supply and make sure it's correct for the number and speakers in use. Easy test is to put your volt meter across the power supply output and watch the voltage as you page and ROP. Should be a steady 24VDC. It might just be old too.

-Hal

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