Analog Dimmer Control

This Standard is intended as a guide for:

1. Equipment manufacturers and system specifiers who wish to integrate systems of dimmers and controllers utilizing analog multipled control.
2. Equipment manufacturers seeking to adopt a basic controller-dimmer analog multipled data transmission protocol

It is important to note that the origins of this standard come from a control protocol originally developed by Strand Lighting (Strand Century Inc.). This protocol is used by a large installed base of equipment manufactured by Strand and many other manufacturers. One of the objectives of the Standard is to describe a protocol that will sucessfully communicate with most of this existing equipment. Because the original protocol has undergone many slightly different versions, this Standard is broken down into two major areas:

1. Receive Timing. Dimmers or other receiving devices that adhere to these timing requirements should be able to successfully communicate with most existing consoles that use different variations of the original Strand protocol.
2. Transmit Timing. Controllers or other transmitting devices that adhere to these timing requirements should be able to communicate with most existing dimmers that use the different variations of the original Strand protocol.

There are substantial differences between the receive timing and the transmit timing. New controllers adhering to this standard must produce a signal acceptable to a wide variety of dimmers, and new dimmers must be able to listen to a number of different controller signals. As an example, note that new controllers should provide a wide "analog valid" window, but new dimmers must be able to cope with the differences in existing consoles, and use a narrow "sample window". These differences in timing between the Receive Standard and the Transmit Standard produce enough tolerance to cover worst case variations on the original Strand protocol.

Although widespread adoption of this Standard is sought by USITT, compliance with the standard is strictly voluntary. Furthermore, it is not intended as a replacement for existing protocols already manufactured, but rather as an addition to existing protocols which will broaden the installed base of controllers and dimmers that can communicate with each other.