Cheap magicq touch screen computer and Chinese Artnet nodes

[paulears]

I put together a really cheap magicq system for my studio and bought a couple of artnet nodes from china to get things working. Might be of some interest, so I made a video. these nodes are half the price of the common ones and seem pretty decent. Computer, touch screen and node for less than five hundred quid?

 

[indyld]

MagicQ has always given multiple network DMX outputs without restriction with no ChamSys hardware requirement. The two Magic DMX dongles do not unlock demo mode, but that is not anything to do with the ArtNet capabilities anyway.

Be interested to know what the deal is with crossover cable vs not, as for one: MagicQ desks (and maybe wings) have internal network gubbins that, in the desks at least, mean a crossover cable is not needed. Two: I can't remember running a laptop for quite a while that does need a crossover cable - isn't that a 2000s thing? Now, if a network switch makes things work then this is generally due to what ArtNet or sACN need from the network.

Assume these boxes aren't RDM compatible, but guess that isn't the market. I would say 'compliant', but assume that word probably doesn't apply to anything in these boxes. Also: Which version of ArtNet? Optoisolated? etc.

Interesting review, thanks.

Edited October 5 by indyld

[paulears]

Interesting? Took me ages to find the crossover adaptor. Without it, no blue light on either, so maybe the PC? 

[indyld]

Just thought, the original wings probably don't have their own network port so one relies on the PC. The bigger desks have a built in switch, with all the functionality that brings. 

The thing with how Artnet and sACN are, they can need an element of 'networky' functions to work properly. This can mean that some kind of switch is needed to make everything behave. Having said that, I regularly use direct connections from a desk to a visualiser using a standard cable. Certainly, I would expect to be able to ping the node from a PC with a network card from the last decade using just a standard RJ45 cable. 

[bruce]

Ah, the old MDI/MDIX thing... haven't come cross that one in practice for years.

With twisted pair networks, and I'm talking Ethernet at 10Mb/s or 100Mb/s (10BaseT or 100BaseT) it was originally common to have "end device" ports configured as "MDI" - ie transmit on pins 1&2, with receive on 3&6. "Network ports" - ie on switches or routers - were configured as "MDIX" with pins 1/2 as rx and 3/6 as tx. 

So connecting a regular "end user" device to a switch - the most common situation - simply needed a straight through cable.

Connecting 2 devices of the same type together - eg 2 PCs back to back, or daisy chaining 2 switches - needed a "crossover" cable. Which was a pain. In the organisation I work for, they were all labelled with yellow tape. Usually.

First attempts to get round this problem was a mechanical switch on one port on a switch - typically the first or last port - which changed the MDI/MDIX status of that port, allowing 2 switches to be chained using a straight thru cable.

Then they came up with a "auto-MDI-MDIX" functionality which, if enabled at either or both ends, would switch a port's status automagically. Works pretty well, as long as auto negotiation (speed, duplex etc) is not disabled.

Gigabit networking (1000BaseT) pretty much made all of this historic, as it uses all 8 pins for both tx and rx, the MDI/MDIX issue does not arise.

So, these days, if you see an issue that's only resolved by a crossover cable, it generally means that it's an older interface, or one where negotiation has been disabled. 

[Stuart91]

The first generation of Roland M-series digital consoles needed crossover cables. (M400 surface, S4000 stage box). 

However the second generation (M200 console, 1608 stage boxes) could switch automatically. 

So, as long as there was one new item involved, any kind of cable could be used. But an old console + old stage box had to have a crossover. 

It certainly caused problems. 

[sunray]

One company I worked for issued 2 metre fairy tale pink cables for us to program some BMS devices, sometimes 2m wasn't enough but adding a f-f coupler to use 2 pink leads never worked, however using a normal grey/red/blue etc extension did. I twigged straighaway why but some of the others thought there was more to it. I confused them by replacing one plug on a 5m green flexible patch lead to make it a crossover and really wound them up by insisting it had to be used the right way round and added pink Dymo lables "commputer end" and "BMS end". For me the pink Dymo was just to indicate it was a crossover cable.

[ninjadingle]

Great review and explanation. One question - does the ArtNet node with the DMX inputs allow merging the ArtNet and copper DMX onto one output? One venue I work in we use ArtNet but they have a DMX input on stage that we might like to keep - the ability to accept copper DMX or ArtNet without having to configure the box would be really useful.

If you're not adverse to secondhand I have bought an older 24" Dell All in One PC for £180 from our favourite auction site. To ensure it works fine I installed Ubuntu onto it so there's no Windows related issues with updates or anti-virus, the touch works great and I've been using it with my PC Wing for a few years. Now moved to a 17" touchscreen laptop (portability and battery backup) running the same setup - Ubuntu and PC Wing. Great systems that don't require a massive amount of computing power or memory, dead reliable and never had any issues!

[timsabre]

Sounds like it won't merge, from Paul's description. You can just manually select outputs to be linked to the inputs for operation as a DMX splitter. More expensive nodes e.g. Luminex Luminode can do this (using a gender changed into one of the outputs)  and are easier to setup from a web interface.

DMX merge can cause some weird stuff to happen and you need to think carefully about how the two signals will be merged - probably you just want to switch to the wired DMX if no Artnet detected or something like that? Rather than actually merging.

[DrV]

Pathway Pathport can do sophisticated merging and splitting but they are expensive.