This, when connected to your HX-20 using a serial cable, simulates an external monitor and disk drive.
The virtual monitor displays on your computer screen and is fully working and (iirc) handles any resolution you request.
The disk drive only implements the file based access commands used by the HX-20, which allows to map a disk directly to a directory on your computer. Consequently, this gives you a virtually infinitely sized disk. The PX-8/PX-4 commands are not supported.
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