Developed at the same time as the Next Generation system, the DVD21 uses infrared controlled drives the same as the X-Rate rather than serial controlled. I think this was a system aimed at operators who had already invested in drives due to X-Rate. Titles exist for Aiwa XD-DV170, Sony DVP-F25 and DVP-F35 drives, I have more than are here right now but these will be recorded in due course now that I’ve worked out how to convert motherboards between drive types.