I've now come across two kinds of special MX6000 sets:
MX6000 AE: Type 76/70 MTI, s/w 2.0 (but upgradeable to at least 2.16)
*One-way (no two-way hardware present)
*Used in Italian video-conferencing system
*May also have been used in hotels
*Custom metal bar along bottom to restrict access to power, STEP button
MX6000 RGB: Type 87/76 KTV, s/w 4.0
*Used aboard Copenhagen/Oslo ferries
