I was reading in the Atari Game Systems FAQ that the 7800 carts are encrypted with a special encryption and only those encrypted games get access to the 7800's advanced video resources (otherwise it just gets 2600 resources)... This was a measure by Atari to make sure to get a share of the profits from 3rd party game developers. There could be a slight possibility this is an encryption unit for the 7800 game system... Currently no one knows (or is saying they know) how to encrypt 7800 carts. Larry Anderson We've reverse enginnered the encryption. I forget the specifics: It was some sort of Public + Private key deal. The key size was 120 *bytes* Not all of a cartridge needs to be encrypted (as little as 4K can be encrypted). Massive overkill for the time. No one has reported finding the keys yet. Probably never will. -Mp