DMX Cabling

The DMX protocol requires using special data cables to accommodate for the high speed digital signals it uses. Despite their apparent similarities, data cables are electrically different from standard microphone cables because they can carry high frequency digital signals and have better protection against electromagnetic interference. You can purchase CHAUVET® certified DMX cables directly from a dealer/distributor or make your own DMX cable.

If you choose to make your own DMX cable, you must use a data-grade cable such as the Belden 9841, which has the following electrical characteristics:

Type:

shielded, 2-conductor twisted pair

Maximum capacitance between conductors:

30 pF/ft

Maximum capacitance between conductor and shield:

55 pF/ft

Maximum resistance:

20 ohms/1000 ft

Nominal impedance:

100~140 ohms

DMX Connectors

Each DMX cable must have a male XLR connector on one end and a female XLR connector on the other end. The DMX protocol indicates that the XLR connectors must have five pins. However, most lighting fixtures use the 3-pin XLR connector. The pin assignment of the 3-pin and 5-pin XLR connectors in a DMX cable is as follows:

Male Plug

Signal

3-Pin

 

5-Pin

Common

1

 

1

 

Data -

2

 

2

 

Data +

3

 

3

 

Not used

 

4

Not used

 

5

Female Plug

5-Pin

 

3-Pin

Signal

1

 

1

Common

 

2

 

2

Data -

 

3

 

3

Data +

 

4Not used

5Not used

You can use the above table to create a 3-pin/3-pin cable, a 5-pin/5-pin cable, or a 3- pin to 5-pin adapter.

The DMX daisy chain uses a terminator to reduce signal transmission problems, especially with long cables. The terminator consists of either a 3-pin or 5-pin XLR male plug with a 120 Ω, ¼ W resistor connected to the wire side of pins 2 and 3, as shown below.

The terminator plug connects to the DMX Out socket of the last DMX fixture in the daisy chain.

Do not allow the common wire of the DMX cable to touch the fixture’s chassis ground. This could cause a ground loop, which may affect your fixtures’ performance. Test all DMX cables with an ohmmeter to verify the correct polarity of the wires, and to make sure that they are not touching the shield or each other.

Scorpion™ GVC/RVM/RGY User Manual (Rev. 02k)

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Chauvet GVC, RGY, RVM user manual DMX Cabling, DMX Connectors