So sharing a printing issue I had with a customer that uses a AS400.
machine has a pf7100 on it. complaint was that when tray 1 ran out of paper and printing from the AS400 it would not go to tray 2 but when printing from word or PDF it would go to the next tray. I had to go the the machine interface and select device setting then paper setting and then group settings 1 then group trays 1,2,3 together. worked like a champ after that. FYI