The RJ-45 connector is now the standard data connector in interior Martin Architectural products. This is because most electrical installers are familiar with this type of connector as well as CAT5 cable, and have easy access to them. The RJ-45 connector is described in the DMX-512A standard and is fully compliant. RJ-45 connectors must be wired as follows:
pin 1.....white/orange.....data 1 +
pin 2.....orange.....data 1 -
pin 3.....white/green.....data 2 +
pin 6.....green.....data 2 -
pin 4.....blue.....not assigned
pin 5.....white/blue.....not assigned
pin 7.....white/brown.....signal common
pin 8.....brown.....signal common
Shield = drain
RJ-45 Connector pin numbering
If a product has both XLR and RJ-45 connectors, never use both the XLR output and the RJ-45 output at the same time, as this will split the DMX link into two branches and cause data transmission problems.
XLR to RJ-45 Adaptors are available as accessories:
XLR 3-pin female to RJ45: P/N 11840086
XLR 3-pin male to RJ45: P/N 11840087
It is still very important to terminate the link at the last fixture on the line. We offer the following termination accessories:
Termination Plug RJ-45:P/N 91613028
Termination Plug XLR, male: P/N 91613017
The 1998 ESTA/USITT draft DMX 512 standard gives the following advice in connection with choice of cable for DMX data transmission:
The data transmission rate (250 kbits/s) used by DMX512 requires the selection of a cable which does not significantly distort the signal or give rise to spurious signal reflections. Cables intended for use with audio systems (microphone cables), while having the convenience of flexibility and availability, have undesirably high capacitance and incorrect characteristic impedance; at DMX512 data rates this will give rise to bit time distortion and signal reflections/overshoot.
Cabling systems shall provide a balanced, nominal 120 ohm terminated transmission line, and be made of cables with a characteristic impedance in the range 100-120 ohms.
Note: Mixing cables of different impedances and other characteristics not isolated by buffers or other processing devices may affect system reliability.
Always use solid or stranded shielded-twisted pair/foiled twisted pair (STP/FTP), 100 or 120 ohm cables that conform to ISO IEC 11801 category 5 or higher with RJ-45 connectors wired as indicated above. The minimum suitable wire size is 0.2 mm2 (24 AWG) for runs up to 300 meters (1000 ft.) and 0.32 mm2 (22 AWG) for runs up to 500 meters (1640 ft.). Your Martin dealer can supply suitable cable in various lengths.