Other Atari 850's

        The first versions of the Atari 850's used black metal cases with white graphics drawn onto the cases.   There are no physical differences in the actual motherboard contained inside of the case compared to the standard 850's which used the beige plastic cases.   Atari at the time may not have decided how they were going to package there peripherals or just hadn't finalized on how they wanted the 850 case to look.   Another possibility may have been for RF reasons, Atari was overly concerned about passing FCC testing (note the excessive use of thick die-cast shielding in the Atari 400/800 computers) and may have packaged the 850 in all metal for fear that since it was an interface system it may have generated excessive RF noise.
        This 850 came out of Lawrence Livermore Laboratories.   It has a Z-80 processor, 6532 and does not utilize the rear RS-232c ports of the unit even though they were included.   it has a IEEE-488 interface and well as a serial cable.   The unit was used to measure seismic readings.