Length of DMX cable a factor?

[3XLion]

Just saw this question.
In case anyone else is wondering.By swapping pins 1 and 2 you were getting half of the signal to your fixture.The normal DMX (called the RS-485 protocol ) signal is what is called Differential.
That means that the DMX receiver works off of the difference between pins 2 and 3.
When pin 3 goes up pin 2 goes down. pin 1 is for shielding the cable.
when you swapped the pins 2 and 1 you only got the goes up part. this would work for a short run of cable but at 300 feet the signal would be noisy and too small.