I was looking around the web for a manual describing the operation of the backlit portable, but nothing. Anyone have a backlit Portable that can tell me how the backlight is controlled?

I was just curious if it is controlled by software or hardware. I know the contrast is controlled by the Portable Control Panel. The PowerBook 100 uses hardware contrast and brightness. Is that because it is passive matrix?

Since Apple claims the ROMs are exactly the same, one would think the hardware and software implementation would be almost identical as well.