You Can Make Your Own DMX Cables
Note: This is bulk cable only. Connectors sold separately.
ADJ makes the high-quality DMX cable your lighting rig deserves. This 22-AWG stranded, tinned-copper-conductor cable provides the ideal conductivity needed for DMX transmission. Two twisted pairs of conductors, an outer layer of dense polyethylene insulation, and a shield of Duofoil and braided tinned copper provides not only solid contact but also excellent DMX signal protection. You can trust your show to ADJ cables. So, while you're looking at Sweetwater's excellent selection of professional ADJ lighting fixtures, don't forget to pick up some quality cables as well. 
ADJ AC5CDMX300 Bulk DMX Lighting Cable Features at a Glance:
Length: 300' spool
For use with 5-pin XLR DMX connectors
Number of Pairs: 2
Total Number of Conductors: 4
Outer Shield: Duofoil Tape/Braid
Overall Nominal Diameter: .295"