WOW You guys are great! 232/422/USB iPhone! Anyone want fries with that? Seroiusly I think these interfaces (LCD Panels, HMI's) are an off the shelf thing purchased and programmed by the automation people. And when they select the HMI they do a features VS price thing and often decide to omit such things as backlights for sake of cost. Now the manufacturer of these HMI's (I'm guessing in Asia these days) has offerings that include backlight in a compatible unit that could be simply swapped out (physically/electrical). There may need to be some beefing up or addition of the power supply to power the backlight (LED's) but the data side would be 'plug and play'. Now I could tear mine apart and photograph the HMI module but I hesitate to do that without a spare in hand- don't want to break my coal stove or loose my fire this 25 degree November morning.
BTW I'll see your 232-422/USB/iPhone and raise you an Insteon home automaion network! Be nice to see it on the Insteon network controlled by my Universal Devices isy99i home automation server! johnk