USITT DMX512, DMX512/1990, DMX512-A

DMX512 is a standard that describes a method of digital data transmission between controllers and lighting equipment and accessories. It covers electrical characteristics (based on the EIA/TIA–485 standard), data format, data protocol, and connector type. This standard is intended to provide for interoperability at both communication and mechanical levels with controllers made by different manufacturers.

ANSI E1.11 - USITT DMX512-A   
Asynchronous Serial Digital Data Transmission Standard for Controlling Lighting Equipment and Accessories  
The ANSI Board of Standards Review approved "E1.11 - Entertainment Technology USITT DMX512–A Asynchronous Serial Digital Data Transmission Standard for Controlling Lighting Equipment and Accessories" on November 8, 2004. ANSI E1.11-2004 was developed under the ESTA Technical Standards Program by the Control Protocols Working Group with input from the entertainment industry via public reviews. E1.11-2004, USITT DMX512–A is available for purchase as a PDF from ANSI's Electronic Standards Store. A hardcopy version is available from PLASA.


The USITT DMX512 Subcommittee, sponsored by the Engineering Commission, transferred maintenance of DMX512 in 1998 to the Technical Standards Program of ESTA (the Entertainment Services and Technology Association) and its Control Protocols Working Group.


On March 18, 2004, the Control Protocols Working Group of the ESTA Technical Standards Program (ANSI ASC E1) voted to accept the last set of public review comment resolutions for BSR E1.11, Entertainment Technology—USITT DMX512–A— Asynchronous Serial Digital Data Transmission Standard for Controlling Lighting Equipment and Accessories, and to accept the draft standard as an American National Standard. See USITT DMX512 - Behind the Revision for more information.  

Some published copies of ANSI E1.11-2004 show incorrect pin numbers in Table 4 on page 15. The pins are shown consecutively numbered, while in fact, they are not. See the DMX512 FAQ for the correct information.


Companion Standards
ANSI E1.27-1-2006, Entertainment Technology - Standard for Portable Control Cables for Use with USITT DMX512/1990 and E1.11 (DMX512-A) Products.    
Digital Data Transmission Standard for Dimmers and Controllers   
USITT DMX512 was originally developed in 1986, and revised in 1990. The 1990 Standard can be ordered from the USITT Office - see the Online Store. In Europe, it can be ordered from PLASA.
DMX512 Over Category 5 Cable    
In response to a perceived industry requirement for lower cost DMX512 cable installations, the DMX-over-Category 5 Cable Task Group was formed by ESTA's Control Protocols Working Group (CPWG) to establish whether Category 5 cable, or "generic premises cable" as it has become known, could be used as a low cost substitute in permanently wired DMX512 installations.

ANSI E1.20-2006, Entertainment Technology - Remote Device Management over USITT DMX512.


See the report on this topic on ESTA's Web Site.

IEC DMX512   
It is important to note that while we have all been using DMX512 since 1986, it is not formally recognized in the "official" standards world. A proposal to make DMX512 an International Standard was submitted to the IEC in the spring of 1999. In August, the application was approved by IEC Technical Committee 34 and the proposed standard was designated "Entertainment Technology - USITT DMX512-A (IEC 62136)." TC 34 formally assigned the project to Sub-Committee 34C (SC34C).


The revision through the ESTA Technical Standards Program (ANSI ASC E1) has resulted in an ANSI standard (E1.11, Entertainment Technology - USITT DMX512-A - Asynchronous Serial Digital Data Transmission Standard for Controlling Lighting Equipment and Accessories) which also provides formal recognition through an internationally recognized standards organization.


Given the international composition and active participation of international members of ANSI ASC E1 and the desire not to subject the standard to potential for additional changes that the IEC process could introduce, the ANSI ASC E1 Control Protocols Working Group has decided not to pursue an IEC standard for USITT DMX512-A at this time. 

DMX512 Hazard - Power on the Data Lines 
There are some manufacturers of DMX equipment that place a voltage on Pins 4 and/or 5 of the 5 Pin XLR connector in clear violation of the USITT DMX512 and DMX512/1990 Standards (and the new ANSI E1.11 USITT DMX512-A version).  Connecting DMX512, DMX512/1990, or DMX512-A compliant equipment, in particular equipment that uses the secondary data link (Pins 4 & 5), to non-compliant gear may disable and/or damage the compliant equipment. For more details, see the DMX512 Hazard Alert

DIN, a German standards organization, has developed a standard for "Stage Lighting Control Systems." The primary emphasis of this standard is an implementation of USITT DMX512/1990. This document from DIN states that all devices which conform to this DIN standard may be labeled "DMX512/1990," "DMX512/DIN" or "USITT DMX512/1990." This means that manufacturers would be able to mark products conforming to two different standards with the same identifier. A user faced with equipment labeled DMX512/1990 will not know whether or not the equipment complies with the original USITT DMX512/1990 standard or with DIN's version.