At the 1994 USITT conference in Nashville, some unfortunate (but not unusual) scheduling took place, with these two sessions running concurrently: "New Technology in Computerized Control of Sound Systems" and "Dimmer Protocol Standards." I ran up and down the stairs, attending both meetings. At the Dimmer Protocol Standards meeting, where the possibility of a future standard was being discussed, I stood up and said, "There's another meeting going on downstairs right now, describing a new sound control protocol in development by the Audio Engineering Society (AES). You all should at least be aware of what's happening, and better yet, you should be active in the AES standards effort." Silence greeted me, then the chairman of the meeting basically said "Next!"

Unfortunately, the lighting community and the AES have continued protocol development in separate vacuums. AES Standards Committee No. 10 (AES SC-10), comprised of representatives of a variety of large and small audio companies, has made tremendous progress on its protocol, AES-24. AES-24 is proposed to be a highly versatile, object-oriented protocol, designed to control any kind of audio equipment from any manufacturer, with or without a master control computer.

A draft of Part 1 of AES-24 has been released for comment. At LDI97, ESTA announced that its Control Protocols Working Group is beginning development on an advanced control protocol for lighting and scenery equipment. The proposed AES-24 might already easily incorporate everything desired by ESTA. It also might not. In any case, both of these systems will someday end up operating in the same buildings, on the same shows.

At worst, these two protocols should be designed to co-exist on a single network. At best, the two groups will get together and develop one protocol for all equipment in a show. The energy and drive of the ESTA control protocols working group would be a great combination with the experience of AES's SC-10 committees.

I urge lighting industry manufacturers to review the AES-24 draft proposals now, and act on them during the comment periods while it is still easy to get things changed. You can get a copy of the draft in print from the AES office in New York by calling 212/661-8528, or go to and click on the hotlink for "DRAFT REVISED AES24-1-xxxx" to download a copy in Adobe Acrobat format.

Please, whatever happens, let's not end up with two control protocols that do the same thing for similar equipment but don't inter-operate.

John Huntington Entertainment control systems consultant, and author of the Focal Press book Control Systems for Live