ANSI E1.11-2004, Entertainment Technology — USITT DMX512-A —Asynchronous Serial Digital Data Transmission Standard for Controlling Lighting Equipment and Accessories, is available for purchase as a PDF or as a hard copy.
ANSI E1.11 is an updating of USITT's DMX512/1990—hence, the "USITT DMX512-A" in the title. The USITT standard was very short (six pages) and loose on some of its requirements. The new version tightens up some of the specifications and adds some provisions for additional functionality. Some alternate START codes have been set aside for common purposes, such as sending diagnostic text data for display and sending checksum data. It also establishes a method by which the number of possible proprietary messages is expanded from the 255 set by the number of possible one-byte Alternate START codes to 65,536. This scheme makes use of a two-byte manufacturer's ID, which is already being used as part of the unique device identifier in the draft standard BSR E1.20, Remote Device Management.
ANSI E1.11 is a much longer document than the original USITT standard, but it is not a wholesale reworking of the standard. The revision was constrained by a desire not to make equipment that conformed to the existing standard instantly obsolete. Anything that fully complies with the USITT DMX512/1990 standard should work with E1.11-compliant equipment.Of course, equipment that does not fully comply with the old standard, such as dimmers that only work reliably with slow update rates, may not work with all E1.11-compliant equipment, but they will not work with all USITT DMX512/1990-compliant equipment either.
ANSI E1.11-2004 was developed by the Control Protocols Working Group with input from the wider lighting community via public reviews. Membership in the Control Protocols Working Group is open to all who are affected by the work of the group; membership in ESTA or any other organization is not a requirement. Affected parties would include anybody that makes, specifies, sells, installs, or uses lighting control equipment. Voting members are required to attend meetings so that the working group can be assured of having a quorum and being able to conduct business, but observer members are not required to attend, although they are welcome if they do. More information about joining the working groups in ESTA's Technical Standards Program is available by clicking here.
The PDF is available from ANSI's Electronic Standards Store. A hardcopy version is available from USITT and will be available soon from PLASA. The list price is $40; member and quantity discounts are available with the hardcopy sales.