@György-Farkas Thanks a bunch! I was stuck as I didn't have an oscilloscope at the time. I ordered one right away and received it the following week. Your response was already in hand.
I "knew" there was the incompatibility as I knew (absolutely) the O2+ 3.3V system and many years of RS-232. However I couldn't find any specifics in the Omega docs of the actual device interface.
Your answer confirmed what I knew. However your answer was much better as it provided a candidate solution to the incompatibility.