On most systems, turbo mode was with the button pushed in, but since the button could often be wired either way, on some systems it was the opposite. On some systems the turbo button was linked to a turbo LED or two-digit segmented display on the system case, although in almost all cases, the indicated frequency (in MHz) wasn't a measure of the actual processor clocks, but the two "fast" and "slow" display options set by jumpers on the motherboard (or a daughterboard linked to the button), or on some later machines, set in the BIOS software.