I did my first show last year with a few dramas (maybe a first year thing I hope). I burnt out 2 X LOR RS 485 adaptors and think it may be current flow getting back through the adaptor, 1 lasted about 2 weeks while the other one only a few days. All the control boards are DC each with its own Switch mode PSU 240V>24DC. I have a few questions: does the RS 485 have a ground reference??? then if so does the rs 485 at the control boards go the -VDC on the board??? do all - VDC have to be joined together to form a common??? and then does that common need a reference to earth??? should I install a isolated usb from the computer to the adaptor effectively isolated it from the PC's earth??? Sorry to fire all these questions around the place, any info would be great.