It's for the HP Portable Plus, HP-150 with HP 45643A HP-IL interface, or PC
with HP 82973A HP-IL interface to run diagnostics on HP SCSI disk and tape
drives. It's most likely not useful for anything else. Definitely useless
with the palmtops.
I'd be interested in high-resolution photos of both sides of the board, and
a dump of the firmware.
http://bitsavers.org/pdf/hp/disc/5960-0163_Using_Mass_Storage_Diagnostics_w…