DMX512 protocol

DMX512 is a digital control signal for entertainment lighting. The DMX512 protocol standard is defined by USITT, the United States Institute for Theatre Technology. The control signal is generated from lighting control consoles and sent to dimmers and other accessories. Prior to the DMX512 protocol, analog control systems were used; zero to ten volt analog was one common standard. DMX512 is a digital multiplexing technique that uses a two conductor shielded data cable to control up to 512 dimmers. Analog systems require a wire for each dimmer channel.

The connector standard for DMX512 is a 5 pin XLR. Lighting controllers and consoles output DMX512 data on a female 5 pin XLR. Dimmers and receiving equipment often have both male XLR's for receiving and female XLR's for looping the DMX512 data to the next device. The XLR with male pins always receives and the XLR with female pins always sends.

The wire for DMX cable must be data cable designed for EIA485. This cable is low capacitance, twisted pair, shielded, and designed for high speed data. There are many brands and types that will work reliably.  Standard pre-built cables can be purchased from any theatrical lighting supplier. Conversion to 3 pin XLR and use of microphone cable is known to be problematic and not recommended.

The pinout for the five pin XLR connector is:

Pin 1

Cable shield wire.

Pin 2

Data Not (also called - Data)

Pin 3

Data (also called + Data)

Pin 4

spare - not used per standard - not connected in DMX-IT products

Pin 5

spare - not used per standard - not connected in DMX-IT products

Shell case

The XLR connector body does not get connected to the cable wire

The DMX512 data signal requires termination at the final connection in the DMX control signal loop. Improper termination is the most frequent cause of DMX problems. A terminator is a resistance at the end of the DMX line. This resistance prevents the DMX data signal from reflecting back down the line and causing data errors and other problems.  DMX receiving equipment should have a "termination" switch or termination option for end of line in the setup. The data signal should only have one termination at the end of the loop, multiple terminations will load down the data signal. If the receiving equipment does not have a built in terminator, then an XLR terminator accessory should be used at the last female XLR "DMX out or loop" connector in the data line connections.

Designed and manufactured in USA by Integrated Controls Inc.
Prices, specifications, features and availability subject to change without notice