At a local electronics trade school where I worked (as a programmer and teaching digital briefly), we had a bunch of Televideo TS-803 Z-80 based CP/M workstations; each had a mouse port, we bought only one mouse tho; it was an early Mouse Systems unit, optical, but requiring the dedicated optical mouse pad. Worked quite nicely, tho, and I wrote a rudimentary drawing program for it to create graphic objects for the computer-based simluation of our digital trainer/breadboard systems.