DMX / RJ45 cable

[sunray]

I am to be doing some work in a venue with 'Ethernet' tie circuits for the DMX (just wall boxes with cat5 between them).

I have 2 questions:

1) What cable do others use?   My plan was to cut flexible RJ45 leads in half and fit XLRs but the 2 I've tried so far melt as soon as a sniff of heat is anywhere near.

2) In this case it doesn't really matterwhat pin out convention is used but I'd prefer to stick with a standard... so far I've found 3 different on www. Is there one preferred format?

[kgallen]

18 minutes ago, sunray said:

2) In this case it doesn't really matterwhat pin out convention is used but I'd prefer to stick with a standard... so far I've found 3 different on www. Is there one preferred format?

Does the pinout here help? Claims to be ESTA.

https://response-box.com/gear/2019/02/rs-232-DMX-engine-rj45-outputs/

Same from ETC:

https://support.etcconnect.com/ETC/FAQ/DMX-512-Info

Cat5:

https://support.etcconnect.com/ETC/FAQ/DMX_Over_Cat5

ESTA:

Edited February 16, 2022 by kgallen

[sunray]

14 minutes ago, kgallen said:

Does the pinout here help? Claims to be ESTA.

https://response-box.com/gear/2019/02/rs-232-DMX-engine-rj45-outputs/

Same from ETC:

https://support.etcconnect.com/ETC/FAQ/DMX-512-Info

Cat5:

https://support.etcconnect.com/ETC/FAQ/DMX_Over_Cat5

ESTA:

That does seem to be 'the popular' version I've found, thinking about it a little bit another version referred only to colours and that swapped the orange and green allocation. It occurs to me the difference between 568A & B also swaps the same pairs.

The other specified 6&3 for data and 4&5 for gnd.

 

Your 4th link shows as broken.

[David Duffy]

I've always used the ESTA standard with data on pins 1/2 and common on pins 7/8.

As for T568A / T568B, it makes no difference as it's just the data pair colour that changes. Common will always be the brown pair.

I've made RJ45 - XLR cables with both schemes and as long as you check the 1/2 pair colour it's not an issue.

[kgallen]

ESTA link: https://tsp.esta.org/tsp/working_groups/CP/docs/DMXoverCat5_P3.pdf

(Link in my original post seemed to work on my phone when I added to the thread but doesn't work on a PC. Maybe the phone cached the pdf?. Fixed link here, can't edit my original post for some reason...)

[sunray]

41 minutes ago, David Duffy said:

I've always used the ESTA standard with data on pins 1/2 and common on pins 7/8.

As for T568A / T568B, it makes no difference as it's just the data pair colour that changes. Common will always be the brown pair.

I've made RJ45 - XLR cables with both schemes and as long as you check the 1/2 pair colour it's not an issue.

Yes I understand the colours of T568A & B and how they can be ignored, what hadn't clicked with me before is one site only referred to colours (in fact it was showing how to wire a 5 pin XLR with cat5 with browns on 1, greens on 2&3 and oranges on 4&5 {being contrary to ESTA}). It wasn't until reading KG's response that the T568A/B format colour flip occurred to me.

[sunray]

41 minutes ago, kgallen said:

ESTA link: https://tsp.esta.org/tsp/working_groups/CP/docs/DMXoverCat5_P3.pdf

(Link in my original post seemed to work on my phone when I added to the thread but doesn't work on a PC. Maybe the phone cached the pdf?. Fixed link here, can't edit my original post for some reason...)

That's a good read thank you. I had a similar problem on another site but one person was able to use the link but only one, the rest couldn't.

The original question is to find out if anyone terminates anything different into RJ45's one end and solders the other end, the problem I've encounterd is when I try to solder, the insulation shrinks back far too quickly on the 2 samples of flexible cat 5 I've tried so far.

[J Pearce]

I’ve happily soldered onto flexible cat5/e/6/a. You need to be quick, you might need a slightly beefier iron than you’d normally use for cable making to get the heat in quickly and localised.

If the soldering isn’t working various of the usual suspects sell some rather smart breakout boxes at a price rather lower than I could make them for.

[sunray]

31 minutes ago, J Pearce said:

I’ve happily soldered onto flexible cat5/e/6/a. You need to be quick, you might need a slightly beefier iron than you’d normally use for cable making to get the heat in quickly and localised.

If the soldering isn’t working various of the usual suspects sell some rather smart breakout boxes at a price rather lower than I could make them for.

I was trying with the usual 7 fine pointed  bit in the weller and getting nowhere, I've now got a large 1/4" 9 bit in there but it starts shrinking back as soon as it touches the copper. Crazy stuff! I've successfully soldered solid before into XLR's (just for peace of mind I terminated some into a XLR plug tonight) but I really don't want to go down that route for these adapters. Equally I'd rather not go down the breakout box route if avoidable and have all the parts languishing here to do the job, ideally I want 6 cables to live in a bag in the bottom of the lighting cables case almost forgotten until required.

 

I know I'm sounding very picky but my kit is very small scale compared to most on the forum.

[david.elsbury]

Turn the iron down… I’ve soldered cat5 cable plenty of times with no issues.

[DrV]

Have you thought of using low melting point solder? Digikey have a range which goes down as low as 118°C.. You can also find it on the auction sites in small quantities. I don't know about the durability of it but it is worth a try. You'll need a decent temp controlled iron of course.

[Brian]

9 hours ago, sunray said:

I was trying with the usual 7 fine pointed  bit in the weller and getting nowhere, I've now got a large 1/4" 9 bit in there but it starts shrinking back as soon as it touches the copper.

I'm not surprised. You've gone from a 700 deg F tip to a 900 deg F tip. In real money 370 deg C to 480 deg C.

Better to keep the temperature down and go for a bigger tip. For XLR's I'd be using an A7 tip; 380 deg C and a 1.6mm chisel. That'll be plenty hot enough for leaded and unleaded solder.

[alistermorton]

Agreed with all the above - I've made (several) batches of patch cables by cutting RJ45 CAT5e patch leads in half and soldering on XLRs and not had a problem with the insulation shrinking back. Some were done with leaded solder, some were lead free, neither caused a shrinking problem.

[sunray]

Problem sorted, I found an old piece of stranded cat5... oh so very different. Almost, but not quite, a pleasure to use. I used my regular go to -  '7' 1.6mm chisel bit, same as Brian.

It seems not all cat5's are equal.

My idea of going to a bigger bit was to get the heat into the copper and get it tinned quickly before it shrunk back.

Edited February 17, 2022 by sunray
Clarification

[David Duffy]

Using leaded solder (63/37 is even better than 60/40) will make it easier too. Lead free solder has a higher melting point.