I remember building embedded control systems with these D5 cards back in the early eighties. You are right, it is an evaluation system, but it was often used for simple prototypes and small production runs. Motorola priced it relatively cheap so engineers could gain familiarity with the 6802, which was an "update" of the classic 6800 processor. The 6802 incorporated the 2-phase clock generator circuitry onchip-- you used to have to add a nuisance clock circuit to make the 6800 run. I think the 6802 also included 256 bytes of RAM (but my recollection's fuzzy on this point.) Since the board also included a little debug/monitor program in PROM, using that hex keypad and display, you could learn a lot about the instruction set just by hooking up a power supply and playing. It was a lot like the KIM or AIM-65 boards for the 6502 cpu. Does the D5 have a large set of edge connect fingers (like, say, 86 contacts or something like that)? I can't remember... Other Motorola evaluation kits, like the D2 (a predecessor of your D5, also based on the 6802 cpu but built as 2 boards--the keypad was separate) had a full electrical interface to Motorola's ExorBus, which was their proprietary general-purpose microsystem bus. They made a full range of heavy-duty industrial boards for ExorBus, and their development systems used it too, so you could build full-blown microsystems with their board sets. This was a competitor to Intel's Multibus in the industrial control market. You could take a D2, when you got tired of playing with it as an evaluation system, detach the keyboard, and plug it in to an ExorBus as the cpu card. It's barely possible I've got some old docs hiding at home... I'll check. Ian McLaughlin <ian(a)okjunc.junction.net> writes: -- Arlen Michaels Nortel Ottawa, Canada (613) 763-2568 amichael(a)nortel.ca