AAH said:You're playing with RS485/DMX and there is no distance requirement other than a max total distance of 1.2km and a maximum number of boards connected of 32. The video is much more likely referring to ethernet and I can't say if there is a minimum distance but the max is definitely 100m.
You are correct. There is a minimum of .5 meters to help prevent electrical bounce between Ethernet devices. I have been unable to find any such minimum for RS485/DMX. There is a formula in the Ti sheet "RS-485 Design Guide", but no specified constant minimum length. (See http://www.ti.com/lit/an/slla272b/slla272b.pdf)