DMX over cat5e

ewsclass66

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Aug 21, 2020
Location
United Kingdom
To transition from Cat5e to stranded wire you should be using something that allows an IDC / Punch-down connection for the Cat5e and possibly a terminal strip for the stranded wire. You just can't / shouldn't solder UTP. Search online and you will find several items that do this in one format or another. Most are RJ45 to terminal strip. https://www.google.com/search?rlz=1C1CHBD_enUS801US807&sxsrf=ALeKk03RQJJBaJXgHSRMxUVMIJ-S9tH_ag:1598457496222&ei=mIZGX438DKqk_Qazs6xg&q=rj45+to+terminal+strip&oq=+to+terminal+strip&gs_lcp=CgZwc3ktYWIQARgAMgYIABAHEB4yBggAEAcQHjIGCAAQBxAeMgYIABAIEB4yBggAEAgQHjIGCAAQCBAeMgYIABAIEB4yBggAEAgQHjIGCAAQCBAeMgYIABAIEB46BAgAEEc6BwgjELACECc6BQgAEM0COggIABAIEAcQHlCyiQJYl8YvYOjcL2gAcAF4AIABgAGIAaAKkgEEMTYuMpgBAKABAaoBB2d3cy13aXrAAQE&sclient=psy-ab

This is something we do a lot of using in-house parts but I'm sure you can find something online.
View attachment 20631
I forgot to mention we ran stranded cat5e instead of solid core for this reason. Going in tomorrow so will do some more testing. Really hope I can find the issue, don't want to run a bunch of new cabling.
 

almorton

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Dec 17, 2014
Location
Caterham, Surrey, UK
Probably obvious, but check every solder joint. Check every termination for the right core going to the right pin. Do you have a RJ45 tester, the sort where you plug a sender in one end and a sort of multiway terminator in the other, and it sends a sequence down and back up the cables showing open and short circuits on LED indicators? Very useful.
 

ewsclass66

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Joined
Aug 21, 2020
Location
United Kingdom
Oops, I should have read more carefully, I thought you were running to RJ45s and then converting from RJ45 to XLR, rather than running CAT5 directly between XLR connectors - my mistake. In which case, the same tests apply, but done manually, end to end continuity, and check for unusually low resistance conductors to conductor and conductor to ground.
Thanks will do, built a small dmx tester with some red leds and 220ohm resistors as well so hopefully that will help fault find.
 

Ben Stiegler

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Aug 3, 2017
Location
Sf Bay Area
Rule of thumb with dmx is if adding a terminator makes things stop working or erratic you've almost certainly got a bad data leg connection somewhere. Possibly a dry joint in one of the connectors. If the gnd is missing it will often still work. Worth making a dmx tester - check out big clive's Youtube for details.
If using a Terminator terminates all lighting control,
There's something wrong with your recent cable pull.
Solder bridges, little wire crumbs, or a nick in the wire,
Can make you declare the situation quite dire.
Inspect with a flashlight and magnifying glass.
If you can't find the problem, start a 2nd pass.

(1 step ahead of the Rhyme Police ... gotta go)
 

ewsclass66

Member
Joined
Aug 21, 2020
Location
United Kingdom
If using a Terminator terminates all lighting control,
There's something wrong with your recent cable pull.
Solder bridges, little wire crumbs, or a nick in the wire,
Can make you declare the situation quite dire.
Inspect with a flashlight and magnifying glass.
If you can't find the problem, start a 2nd pass.

(1 step ahead of the Rhyme Police ... gotta go)
Well I solved it, I soldered the patch panel completely wrong 😂 re-soldered today and worked like a dream. Soldered the inverse of what it should have been.
 

theatremgr

Member
Joined
Feb 7, 2020
Location
Saginaw, Michigan USA
Termination is not optional. For successful, consistent operation and static protection all risers need to be terminated after the last fixture.

Winkin' blinkin' of random instruments are not very useful in any production.

The integrity of the digital signal is necessary for successful operation of the DMX control system.
 

RonHebbard

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Premium Member
Joined
Jun 12, 2004
Location
Waterdown, ON, CA
Termination is not optional. For successful, consistent operation and static protection all risers need to be terminated after the last fixture.

Winkin' blinkin' of random instruments are not very useful in any production.

The integrity of the digital signal is necessary for successful operation of the DMX control system.
Also, terminating a line pulls more signal down the entire length of each terminated run improving signal to noise ratio.
Toodleoo!
Ron Hebbard
 

Ben Stiegler

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Joined
Aug 3, 2017
Location
Sf Bay Area
This Canadian worked for a Canadian company contracted to build five, fully populated, 44 RU racks for an installation on the Strip in the heart of Las Vegas.
Tussauds in England paid my boss to supply, pre-wire, ship, and supervise the on site installation; two of us were there for a few days longer than four months to install, program and test "On other people's money" as the phrase goes.

The two of us were put up in separate rooms in an all suites hotel with a fridge in every room, our 24/7 buffet breakfast included, and a row of taxis out front waiting to ferry us down town once or twice daily "On other people's Money.

A 20 hour per day brew pub was immediately next to our front door where we purchased our own dinners EVERY evening seven days per week for a few days more than four months.

Never having seen the installation skills of our local IBEW crew, we packed more than fifty each of Neutrik Male and Female XLR-three's, fours, fives and sixes. We only needed to install ONE XLR 7 pin Male on site; we packed one + one spare.

You don't want to view the artful remnants of the first connector one of our best local crew "created" soldering free hand atop a personnelle lift using an iron better suited for sweating together 10' lengths of 1970's galvanized metal eaves trough.

To the gentleman's credit, he definitely gave it his best for approximately two hours. When finished The connector's pins were neither parallel nor of a similar length. It got "interesting" when I threw a 7 contact Female up to him to try mating it,
The gentleman could terminate Twistlocks from 2 contacts to 5 / 15 amps to 30 but Neutrik 7's were not in his skill set.

During his coffee break he decided this was an impossible task and agreed to my riding a scissor lift, with him along to observe, and prove before his own eyes that terminating 6 or 7 conductors of foil shielded 22 gauge stranded could actually be accomplished sans creating a mound of smoldering plastic with seven tiny pins stuck in at jaunty angles.

Live and learn and preferably on "Other people's money".
Toodleoo!
Ron Hebbard
@RonHebbard what were you running on XLR-7?
 

RonHebbard

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Premium Member
Joined
Jun 12, 2004
Location
Waterdown, ON, CA
@RonHebbard what were you running on XLR-7?
Sorry Ben; The Tussaud's Vegas project was 1999. I've forgotten the precise details but I'll never forget the XLR 7 male insert as a molten hunk of plastic with non-parallel pins of various lengths embedded in it.

As a total guess, it was likely a combination of 5 pin DMX with the last 2 pins serving as a convenient way to mate two contacts of DC control without having to make panel space for another connector. We were only doing this in one location on the entire project and had already made, engraved, and assembled the panel in our shop. With it being the only XLR 7 Male cable end we needed to install on site, we only packed two, thinking one and a spare just in case. When the first connector was turned into a creative art piece, I KNEW my boss wouldn't want the second connector to meet the same fate.
Toodleoo!
Ron Hebbard
 

RonHebbard

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Premium Member
Joined
Jun 12, 2004
Location
Waterdown, ON, CA
Didn't 90s era Strand lighting desks have XLR 7 for their remote focus unit?
In my memory, our brand spanking new LP90 with first generation software used an XLR 6 for its remote.
XLR 6's were infamous for their TWO, non-intermateable, configurations:
The original Cannon style and the newer Switchcraft style commonly found on Clear Com packs and base stations.
When Neutrik came into existence, they wisely offered XLR6's in BOTH configurations; customer's had to careful which configuration they were ordering.
Toodleoo!
Ron Hebbard
 
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RonHebbard

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Premium Member
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Jun 12, 2004
Location
Waterdown, ON, CA
Ron,

There is nothing that reduces noise quite as well as shielding. Not available on naked CAT 5 Conduit helps.
@theatremgr I'm not disagreeing with you but I'll reiterate my point.

When you operate your DMX lines unterminated, you're taking a comparatively low impedance source, routing through an EMI rich environment with each comparatively high impedance device essentially bridging the non-terminated DMX line.

Terminating each individually driven run achieves two important things:

1; Pulls more current from the low impedance source thus pulling that current all the way to the far end of each run. The level of EMI and RFI accumulating on the length of the line is what it is. Drawing additional current definitely improves the signal to noise ratio at any / all points along the length of the line.

2; Terminating the line at its far end minimizes reflections back towards the low impedance source potentially creating timing errors for the comparatively high impedance devices effectively bridging the line at various points along its length.

Optimistically I've better explained my points.
Toodleoo!
Ron Hebbard