Tone Decoder Control System

The Tone Decoder Control System encompasses a family of animatronic show controllers designed by Creative Engineering Inc. in the late 1970s for use with their early shows. It is believed that there are multiple variants of this control system, primarily differing in the number of supported output channels, modified as needed for each show type.

Hardware
The Tone Decoder Control System was primarily comprised of a number of tone decoder modules, which were custom made by CEI. These modules, as the name implies, detect the presence or absence of a tone at a specific frequency in their input audio signal, and switch their outputs accordingly to control character valves and other show systems. Each module appears to be potted in a PVC pipe fitting, with a vacuum tube style plug connecting to the backplane.

As the precision of tone detection using analog electronics is relatively limited, the specific frequencies used would have to be spaced apart to avoid interfering with each other. Other drawbacks, such as interference due to the harmonic relations between different tone frequencies, must also be taken into consideration. Due to these factors, this control system family typically used relatively large multi-track tape decks for show storage, with each tape channel driving only a few decoders (in addition to channels set aside for the show's audio program). This way, the same frequencies could be reused on different tape channels.

Shows known to have used this system

 * Jingle Bell Jamboree (prior to 1979 upgrade)
 * Wolf Pack 5 (original shows - possibly upgraded to Pianocorder-based control in some cases)

Contemporary usage
Advancements in show control technology rendered tone-based systems obsolete by the 1980s. Notably, however, the Animatronics Experimenter's Kit includes two tone decoder modules. These modules are believed to roughly follow the original CEI design with minor differences.