Why are people not exploring their phones????
I found this the day I got my N900... PR1.1 and before probably.
I don't know it's use, but what's the point of knowing without the code?

It's most likely a carrier supplied code. Some phones can be carrier unlocked by typing a code into the keypad with a few #'s and *'s to unlock. This is probably similar, from the days when Nokia thought the N900 would be a good, high selling phone.... Oh, how wrong they were!