Unlike A600 the newest model A620 has no jog dial. But I found a brochure for A620bt some days ago that has an error: it says jog dial in the place where should be stated infrared. The link is
Its an entry level PDA and thats why it lacks jog dial. Anyway the jog dial on my old A600 was just awful so I'm not concerned about that on my future A620bt.