Gee. One I can answer. I'm not a collector like you folks, but I did use Kaypros and other CP/M machines for about a decade. The Kaypro 4 is your basic Kaypro transportable with a Z80 CPU (probably 4 MHz) and 64K RAM. It has two DSDD floppies which give 390K each in Kaypro's format, which is where the "4" comes from. At some point in 1984 or later, Kaypro switched from using Roman to Arabic numerals. Thus the 4, as opposed to the IV, is a later machine. Some of the later machines had a built in 300 bps modem, but if memory serves those all had "X" suffixes, as in Kaypro 2X (which paradoxically also had DSDD floppies, not the SSDDs of the Kaypro II). --Dav david_a._vandenbroucke(a)hud.gov