Success. Thanks for all of the suggestions. It might have helped if I hadn't thought that the system was a 308 when it is a 509. So, looking in the wrong manual didn't help.
I did end up defaulting it (there was no PCMCIA card) and starting from scratch. While programming and pressing Next Procedure I noticed LOUDSPEAKER PAGING LINE (#617 ?) and assigned Line 5. Then I programmed "Page" buttons as I70 and moved the line cord from PAGE JACK to LINE 5. Test pages worked fine. I still don't know why using the Page Jack didn't work, but TAH DAH!
Thanks again.