I have three Belkin F1D080 Omniview PS/2 MAC Adapters on Ebay, item
#110092462075. They allow you to use a PS/2 type keyboard and mouse on
older ADB equipped Macs, as well as a VGA/SVGA monitor. They also work on
Apple IIGS systems, as long as your monitor can sync to 15KHz.
Mike Loewen mloewen at cpumagic.scol.pa.us
Old Technology
http://ripsaw.cac.psu.edu/~mloewen/Oldtech/