Cable length confirmation
Looks like maximum runs of about 500-600 meters (so around 0.4 of a mile).
He has specified that the installer must use the cable that is specifically designed for DMX/RS-485. Equivalent to a Belden 9841 or 3105a. Is this ok?
Is a cable specifically designed for DMX/RS-485, Equivalent to a Belden 9841 or 3105a, okay to use over 500-600 meters?
It should work. Normally the wiring issues are connections, so please use all three wires, the ground (shield) is needed.