DMX over Cat5

[PaulDF]

I have had a look at the Wiki and linked sites and I understand I can use Cat 5 UTP for DMX.

For the fixed part (about 15m) I was wondering if I can run 2 universes down a single Cat 5 cable? Is this what the Data 1 and Data 2 are referring to?

Or is Data 2 referring to the data from pins 4 and 5 from a 5 pin XLR DMX cable?

Thanks

 

Paul

[J Pearce]

Data 2 is Pins 4/5 yes.

No reason that you couldn't use it for a second universe in the same way that Avolites do, though it would make it harder to implement RDM should someone ever find something useful to do with it.

[PaulDF]

Thanks, pins 4&5 are not connected in any of the leads I have so isn't much of an issue that way.

I just like the 5 pin plugs and sockets as they can't as easily be mixed up with the sound guys, shame some of the manufacturers don't seem to agree!

[Tomo]

Data 2 is intended as "Secondary Data Stream", so it's acceptable to use it as a second universe down the same wire.

- This has quite often been done with DMX installed cable, either for later expansion or if a cable got damaged, to avoid the expense of opening the trunking and pulling extra or replacement cable.

 

RDM uses the same physical pair of wires as DMX, so there is no worry about a clash in that respect.

While there are some devices that use the secondary stream as 'talkback data', these are proprietary systems so if you don't currently have one, you're unlikely to need it in the future.

[PaulDF]

I have just ordered some 5pin XLRs panel plugs/sockets from CPC for the fixed wiring so will give it a go and will let you know how I get on.

Cheers

 

Paul

[Davethsparky]

Don't forget you need IDC connections for cat5 cable not solder or screw terminals.

[TomLyall]

Don't forget you need IDC connections for cat5 cable not solder or screw terminals.

 

For stranded core, you want solder or screw terminals. For solid core, IDC is easiest, though solder would also work.

[PaulDF]

I have ordered XLR panel sockets/plugs which require soldering, I didn't think about IDC.

What is the reason soldering shouldn't be used, all my leads are soldered?

[PaulDF]

I have now installed the cable, slightly longer than expected at 26m. Am waiting on parts from CPC which will hopefully arrive tomorrow.

[david.elsbury]

26m should be no problems at all, my install at church is around 60 - 80m and poses no trouble

 

Cheers

[paulears]

The IDC thing is just because CAT5 is normally an IDC fitted system. There's no reason you can't solder, in fact, you have to, as I've not yet seen 5 pin IDC panel mount connectors. CAT5 solders fine - just bend the end back on itself just wider than the solder bucket. Then it stays in place. Minimum heat for minimum time, and heat the bucket not the conductor works for me. The insulation shrinks back on the cores if they get too hot!

[Tomo]

The IDC thing is just because CAT5 is normally an IDC fitted system. There's no reason you can't solder, in fact, you have to, as I've not yet seen 5 pin IDC panel mount connectors.

It's actually a standard part from ETC, although usually sold pre-fitted into custom faceplates/rack connector strips.

The 8-pin 'Phoenix' connector ETC uses for DMX is available in screw-terminal and IDC variants. (It's 8-pin so that you don't have random 'spare' conductors hanging around from the Cat5.)

 

There are tales of woe regarding soldered connections to installed solid-core wiring, I think mostly related to poor solder joints as there's no wicking effect.

- Basically it's very easy to get a dry joint.

 

Although they do tend to be more fragile than solder joints to stranded wire, for an in-wall installation that probably doesn't matter so much.

[PaulDF]

Thanks to all that responded, I have now got the CAT5 up and running. I have tried each of the universes individually and works a treat, I'll still need to try them in tandem.

 

Paul