Issue #2, March 1996
The response to our first newsletter was tremendous. We received many requests to change the contact person, some requests to add additional copies to branch offices, and a few who didn't need to receive the information. I hope we made all the requested amendments. If we missed a few, please let us know.
USITT.At our dealer training session, held at the USITT convention, we demonstrated what happens when 120 volts AC is placed on the DMX512 line. As you might guess, stuff blows up, literally! Many of our products have protected inputs and outputs. These survived without failure (other than a few fuses). Our model 123 is not protected. It smoked when 120 volts was put on its input and blew the top off a chip when 120 volts was placed on its output. Pretty neat! The winner for the most explosive result was the ETC response opto-splitter. The ETC unit blew up so loudly that we all jumped. When we got back home we evaluated the failures of our units and the competitors' products. These kinds of experiments and evaluations allow us to continually improve our products, not to mention the entertainment value!
As a result of the experiments at USITT we found a way to improve the protection offered by our standard splitters (models 123, 125, and 1211). If subjected to 120 volts on the inputs or outputs these models may occasionally fail in such a way as to place high voltages on adjacent circuits. Limiting a fault condition is one of the purposes of an optically isolated splitter. To improve the fault limiting capability of our standard splitters we are adding protection against explosive failures. The new models will still fail when subjected to line voltage on their inputs or outputs, but they will fail politely.
125E Improvements.Our top of the line splitter (which is protected against line voltage on its DMX lines) is getting even better! Starting in April the 125E will sport 5,000 volt isolation on its transformers (up from 1,500 volts). We are trying to get the CE mark on this product to allow it to be sold throughout Europe. One requirement for CE marking is higher line voltage isolation, hence the new transformer.
Following last month's newsletter Steve Carlson of Rosco/ET pointed out another advantage of the MAXIM driver used in our model 125E: The slew rate limited output reduces Electro-Magnetic Interference (EMI). EMI reduction is another requirement for CE marking. Thanks for the observation, Steve.