From http://epccs.org/hg/open/RPUadpt/

Shield used to connect a node to a RPU_BUS, which is multidrop full duplex RS-422 (RX and TX pairs) with an out of band half duplex RS-485 (DTR pair).

RPUadpt Board development and hardware.

I am using Makefiles and am hopeful the files can be kept to a manageable size.

Makefile setup http://epccs.org/indexes/Document/DvlpNotes/LinuxBoxCrossCompiler.html