I have a customer that wants to hear ringing over a loud speaker on all 4 lines. Can someone tell me if I am on the right path. I would connect a Valcom 9924C Audible ringing unit to extension port 27. Then use a Valcom 1030C horn with power supply. I would leave ext. 27 in the same ringing group as the other extensions. Would I need to designate that as a PA port? Your input and help is appreciated.
Craig

I think what you want to do will work. If using just a single trigger you could use a cheaper night bell over paging adapter.

You could also use a Wheellock UTA-WH-VPS to provide both audio and visual notification.

Regardless you would need to designate the single line port as a PA port.