I needed an Atari 800 for a project this morning, so went down to the basement to grab one. I've had this machine for years but don't think I've powered it on before. Don't remember where I got it.
It has a sticker from Encore Video Productions (Myrtle Beach SC) where the Atari 800 logo should be. And an unusual jack added to the back. But the most interesting thing is when you start it, you don't get MEMO PAD; you get:
INFORMATION DISPLAY SYSTEM
By Dean Wittmann and James Marshburn
for ENSIGN COMMUNICATIONS
It appears to be a system for displaying messages on a TV, for instance at a TV station.