Newsgroups: rec.arts.theatre.stagecraft
Subject: Re: Build your own...
References:  <[email protected]>  <[email protected]>  <[email protected]>
"Frank Wood"  writes:

> Of course transformers and DMX do not mix. DMX is a digital signal, and
> straight audio is analogue.

Signal being digital does not necessary mean that the transformers 
cannot be used. There are wide variety of digital signals, some 
can nicely go through transformers and other can't. For example 
digital audio (SPDIF and AES/EBU) and Ethernet (10Base-T etc.) signals 
will go nicely through transformers. If the signal is designed so that 
it does not have a DC component that has significance, then 
the signal can be passed nicely through suitable transformer. 
This applies in analogue world as well. You can pass audio signal 
and some video signals through suitable transformers nicely, but 
running 0-10V DC dimmer control signal trough isolation transformer does 
not work.

DMX-512 digital signal waveform is such that the signal DC level 
has significance to the operation of the system. For this reason 
it does not work nicely with isolation tansformers. 
So isolation transformes cannot be used for DMX-512 signals. 

-- 
Tomi Engdahl (http://www.iki.fi/then/)
Take a look at my electronics web links and documents at 
http://www.epanorama.net/