D54 and MPX protocols

[MNicolai]

So after our portable Strand 300 Series bit the dust after our outdoor concert season last summer, one of my coworkers called a friend up, said we needed a two-scene preset for under $1000, and then next morning overnighted from Cleveland we had a Strand Mantrix MX 24 in our hands.

We setup our outdoor stage today, brought in our audio company, and got our entire space ready for the season, complete w/ overnight rent-a-cop to keep the equipment protected until tomorrow's show. We cracked out the Mantrix and Martin was about to plug it into the audio company's touring dimmer rack, but it accepts MPX, but they also provide a DMX==>MPX converter, however he wanted to set this up without converting the signal. Anyways, he asked me about D54, because it's a 3-pin output, and the MPX is a 3-pin input, and wanted to know if that's the same. He's been in the business for many more years than I, and until today I had never even heard of D54. Lo-and-behold, it works. I'm sort of curious now though, what are the differences and simliarities between D54 and MPX that it works without a problem. I wasn't able to find much on D54 besides that all of the dimmer levels can be seen on an oscilloscope.

Does anybody know anything about D54 and why it works without a hitch?

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Better Question, how does D54 relate to AMX, DMX, SMX?

[sound_nerd]

I was always under the assumption that D54 was a Strand-only protocol, similar in function to AMX-192 but with half of the channels. So it'd be an AMX-96 sort of.

If I'm wrong, someone please correct me!

[dramatech]

It has been some time, since I have worked with a Mantrix, but a possible answer to your question might be, that in the early development of Mutiplexed protocalls for dimmer control, there were many companies with their own analog muliplexed protocalls. Lightronics called theirs LMX, NSI called theirs NSX. Leprichon had their own and Strand had their own.
The realism of it all was that they were all very similar and really worked on an unbalanced signal that was serial much the same as the early RS-232 only each bit in the serial chain was actually different in amplitude based on which dimmer it was controlling.
The major difference between these various protocalls and AMX-192 was that the AMX-192 was a balanced system and sent individual clock circuits to tell the serial receivers (dimmer racks) when to reset for the next serial scan.
The sytems used a three pin XLR for several reasons, of which one was so that they could use mic cable. A second reason was to identify them from AMX-192 (4 pin) and of course later the DMX-512 protocall used 5 pin to keep it identified seperately.
On the systems mentioned, one pin (1) was used as a ground for the signal and a voltage. One of the other pins,(I don't remember which ) was used for the signal and the third one was used a voltage so that the first dimmer in the line could power the board. This voltage differed from manufacture to manufacture and was sometimes AC and sometimes DC and the voltages also were different. Lightronics actually switched what they started with to the same as NSI to make them compatible. Most all of the systems could run the others dimmers from their boards as long as they didn't use the phantom powering from the dimmer pack. A few years ago NSI quit using the term NMX and started calling it MIcroplex because it was compatible with other manufactures. some of the other manufactures, while maintaing their original terminology point out that it will work on Microplex, if using an external power supply to the board. I know that might be a little confusing, but I hopw that it at least helps you understand a compatability that might not be stated.