After some further reading, I've found that the 4P supports booting from its RS-232 port, a feature which was used for production testing. So, given that feature, the 4P *needs* something like ADTpro or DW/Wired! Hmm, it might be time for me to learn Z-80 assembler... :) -- Mark J. Blair, NF6X <nf6x at nf6x.net> http://www.nf6x.net/