I can't see how to specify a signal as having inverted logic. I've hooked up the GPIB bus for analysis, and this bus uses active low logic. For the discrete control bits, I don't really care. But for the 8-bit data bus, wow, that's a headache to interpret when the hex data is inverted. For example, sending 'BUS' over GPIB is logically sending hex bytes 42, 55, and 53. But physically and on the logic analyzer you see BD, AA, AC. This makes checking GPIB transfers extremely awkward.