I'll take a stab at this. I may be answering the wrong question. Modern lighting consoles are switching from
DMX to a variety of
Ethernet control systems. For now they are proprietary but in the near future they will be standarized to
ACN. The manufacturers of intelligent devices have not made the
switch to
Ethernet control yet... I think they are waiting for
ACN to be implimented first otherwise they have to deal with multiple protocals which would be really a pain for them.
So someday you'll be able to run a cat 5 cable directly to all your devices. But for now we need a
Node to translate the proprietary
ethernet control back to
DMX. So you run cat 5 to the area near the intelligent device, then
plug it into a
DMX node which translates it back to
DMX.
DMX nodes can also be used for input devices. If you have a
Strand system connected by
Ethernet. You can control it with an
ETC console by runing the
ETC console on a
node set to input. This will translate from
DMX coming out of the
ETC console into
Strand's
Ethernet language. There is a negative side of using a
node to input. The
ethernet systems have two-way communication,
DMX does not. So if you put a
console on one of these networks using a
node it can talk to the
network but can't listen back... which will become very important when
RDM* comes along.
*
RDM= Remote Device Management (Sort of like "
plug and
play" for lighting systems). In the near future , you will be able to
plug an intelligent device in and it will identify itself to the
network and your
console will know exactly what device you have and where it's at on the
network. Making setup easy.
ETC and
Wybron had a working demo of this recently at
LDI 2008.