S-100 Serial I/O options

Hi all -- I am one step closer to having a "useful" IMSAI 8080; thanks to a kind listmember I now have more spare 2147s than I know what to do with, and have used them to repopulate my 32K static RAM board. That brings me up to 48K of working RAM, which seems like more than enough to play with. Now I'd like to get the IMSAI talking to the world. Or at least a terminal. (Gotta start somewhere.) Were there ever any standards for serial I/O in the IMSAI/Altair/S-100 world (ports, interrupt settings, etc)? I have an IMSAI MIO board that I'd like to use. It has more configuration options than one can shake a stick at, and the (185 page) manual makes mention of several port address configurations, referring to them as "IMSAI SIO," "Processor Tech 3P+S," "Altair SIO." Did one of these emerge as a de facto standard at any point? My _eventual_ goal is to run CP/M at which point (hopefully) I assemble a CBIOS for whatever serial configuration I end up with and it's all taken care of; for now I'd be happy to get some paper-tape software to run. (Altair BASIC might be nice.) So I'm trying to work out a serial configuration that will work with a fair amount of archived software -- what would you recommend? Is the MIO board a decent serial board, or should I find something else? Thanks as always, Josh