Here's the 4 way P-DMX splitter design that was discussed in chat over the last couple of days. One MAX485 is for the input, while each of the other MAX485 chips feeds two outputs. This is ok as this is an implementation of a mid-span driver. The input is also P-DMX and has a loop output so you can effectively get 4+1 outputs. A DC input connector and fuse is provided for using this board as a P-DMX injector. I have provided an LED to indicate presence of the 5V power. The P-DMX voltage can be disconnected from the RJ45 sockets by simply removing the fuse. Board size is approx 100mm x 35mm and it screws neatly into a Jaycar HB6122 plastic enclosure.