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8) DMX 512 Information
The following information is a summary of the USITT 1990 standard for dimmers and
controllers. A complete copy may be obtained from:
USITT
10 W. 19th ST.
Suite 5A
New York, NY 10011-4206
Several web sites exist that have an abundance of information regarding DMX-512. As
with any Internet information, consider the source.
The DMX 512 standard is designed as a simple, reliable system for connecting digital
dimmers and controllers. The protocol allows up to 512 dimmers to be connected to a
single control console. With 512 dimmers in a system, DMX 512 allows each dimmer
level to be updated 44 times each second.
Connectors
The DMX standard specifies the use of 5 pin XLR connectors. DMX 512 currently uses 3
pins of the 5 pin connector. Pins 4 and 5 are reserved for future use. Some
manufacturers are using these pins for communications back from the dimmer to the
control console, or as a redundant data line.
The connectors to be used for DMX 512 are as follows:
Console end (transmitter)
Female 5 pin XLR
Dimmer end (receiver)
Male 5 pin XLR
Some manufacturers of XLR connectors are Switchcraft and Neutrik.
Cable type
Shielded twisted pair approved for EIA-422/EIA-485 use. Either one pair with shield or two
pair with shield may be used. Examples of such cable are:
Single pair: Belden 9841, Alpha 5271
Two pairs: Belden 9842, Alpha 5272
The Pin Designations for DMX 512 are as follows:
Pin 1
Signal common (cable shield)
Pin 2 Data 1-
Pin 3
Data 1+
Pin 4
Spare, optional Data 2-
Pin 5
Spare, optional Data 2+
