In the not-too-distant past, playing back the cues for a production required a complete, dedicated lighting console, even if the same set of cues was being endlessly repeated in a son et lumiere, a museum exhibit, a retail display, or architectural control. The adoption of a standard digital communications protocol (DMX512), together with the advent of the affordable and (relatively) reliable microcomputer, has produced several generations of computer-based controllers. Control desk software is loaded onto the computer, which drives either a DMX interface device, or is fitted with a DMX communications card. Today, playing back the cues for a production requires a complete, dedicated computer, even if the same set of cues is being endlessly repeated.

DMXPlayBack from ENTTEC in Melbourne, Australia, looks very similar to many of the devices already available: A computer connects to the half rack-width box, which puts out a stream of DMX512. The resemblance however, is entirely superficial. The computer, which can be either a Windows system or a Palm PDA (personal digital assistant), is only required to configure and program the PlayBack via its RS-232 serial port. Once the cues are loaded, the PlayBack is a complete standalone DMX512 controller that can run any one of the 26 show sequences in its non-volatile memory.

Built around a high-speed integrated processor chip which handles all input, fade processing, and output, the PlayBack can store either snapshots of an incoming DMX stream or scenes downloaded from a computer. The channels actually being stored in a snapshot can be defined, although the PlayBack always generates a full 512-channel frame. Using the optional data compression capability (where only the changes between cue states are recorded), it can store up to 2,000 scenes together with their delay and fade times.

Replay of a show sequence can be initiated by powering up the PlayBack, by a switch closure on one of the external inputs, or by an instruction received via the RS-232 socket. The number of times a show sequence is to be repeated can be defined, or the device may be configured to repeat a sequence, only while the switch on an external input is held closed.

The accompanying control software is a serious implementation of a control desk, with an expandable library of robotic fixtures, and a standard ICBF (intensity, color, beam, and focus) approach to attribute editing. While lacking some of the bells and whistles of a Flying Pig Systems Wholehog II, the software is certainly more than sufficiently serviceable to put together a basic production. Besides, if you need the functionality of a Wholehog, you can bring one along to do the programming and capture each scene into the PlayBack. The control software, which is currently available for the Windows (95/98/ME/NT/2000) or the PalmOS PDA platforms (PalmIII, IBM WorkPad, Handspring, etc.), may be downloaded free of charge from the ENTTEC website at www.enttec.com. The concept of being able to make adjustments to the program in an installation with the PDA in your pocket, rather than dragging out the Avolites Sapphire yet again, is very appealing.

Perhaps one of the most exciting features of the PlayBack is the publication of the RS-232 communications protocol for the device. This allows anyone to develop their own applications to drive the PlayBack. More importantly, it allows the PlayBack to communicate with any device with a serial port, such as a show controller, an energy management system, a smart home controller, or even a modem. Not only does the PlayBack execute cues on serial command, it also confirms that execution is complete, something your console operator never has time to do.

The DMXPlayBack is CE-approved and available now from ENTTEC for US$350.