?
It certainly didn't have market penetration in USA!
I did once have, and implemented in XenoCopy, a sample disk from an Okidata if800 model
20, which seemed to be the same as a BMC if800 model 20 (if one more alternate name might
help you find information). I hadn't heard the Sumicom badging.
?
I also had a disk for Oki (don't know if same model) with the Microsoft Stand-Alone
BASIC, instead of CP/M.
?
Unfortunately, the model 20 was a different architecture all together. I have begun
looking into Japanese museums. Maybe there is more documentation and data in its country
of origin.