Phil,
It's been a while since I had my FTV-901R/FT-980 connected together, but I did a test with one of my '980s last night (w/o transverter). The V/U button doesn't have an effect, and the Operating Manual (which describes its function) seemingly bears this out. You must have a transverter connected to the radio and the appropriate lines on the ACC connector toggled before the button will change the display.
73 - Fred, N8YX
