Another factor is that whenever you have one of those
connector boards with the feed off to the chip, you introduce a
reflection point that can contribute to the noise on the
line. As small as the area is, it breaks the
impedance of the twisted pair. To a lesser extent, it is why you should use one 100
foot cable as compared to four 25
foot cables plugged into each other. Each time the
line comes to a
connector, the twisted pair
line is broken, runs straight through the
connector pins, and then resumes twits. No studies (that I am aware of) spec out what harm the connectors introduce, but anyone with an RF background (
DMX is at heart an RF signal traveling through a transmission
line) knows anything that disturbs the "transmission
line" desegregates the signal. (Thus, the coaxial connectors in RF)