Two different questions arrive with the same five words. One is “can I put the DMX512 signal on a Cat6 pair instead of buying DMX cable?” The other is “the console has an RJ45 output — is Cat6 the right cable for that?” The first answer is no. The second answer is yes. Both mistakes look identical on the bench, which is why they get made.
Short answer
| What you are trying to do | Is Cat5e / Cat6 the right cable? | What is correct |
|---|---|---|
| Send the DMX512 bus signal down one pair of a network cable | No — the cable is not the impedance the bus expects | DMX512 / RS-485 cable: 120 Ω shielded twisted pair |
| Carry DMX universes over Ethernet (Art-Net, sACN / E1.31) | Yes — this is what network cable is for | Cat5e / Cat6 cable plus a gateway or node that outputs DMX512 at the fixture end |
| Replace a damaged DMX lead with whatever is in the van | Only as an emergency, and outside the standard | The correct DMX512 cable, kept as rental stock |
Two different things are called “DMX over Cat6”
DMX over Cat6, meaning the bus signal on a network pair. DMX512 is an electrical bus. The controller drives a differential pair, and every receiver on the chain listens to that same pair. What travels on the wire is a bus signal with a defined characteristic impedance, not a data packet with an address.
DMX over Cat6, meaning DMX-over-Ethernet. Here the universes travel as Ethernet frames. Two free-to-use protocols do this: Art-Net and sACN (ANSI E1.31). At the fixture end a node or gateway converts the frames back into a conventional DMX512 output, and from that box onward the signal is the same 120 Ω bus as always.
The cable follows the port. If the console presents a 5-pin XLR DMX output, the cable on that output has to be DMX512 cable. If the console presents an RJ45 network port, the cable on that port is network cable — and the DMX512 signal only reappears after a node.
What DMX512 specifies about the cable
The DMX512 electrical specification (ANSI E1.11, with cable guidance in E1.27-1) describes a shielded twisted pair with a nominal characteristic impedance of 120 Ω, terminated at the far end of the bus. The connector is 5-pin XLR: pin 1 signal common, pin 2 data 1−, pin 3 data 1+, pins 4 and 5 the optional second data pair.
Two details from the standard are worth carrying into a cable order:
- Termination and impedance are the same number by design. The terminator is a 120 Ω resistor across the data pair, and it works because the cable is also 120 Ω. A terminator cannot correct a cable whose impedance is a different value — it can only match the cable it is fitted to.
- The 3-pin XLR that most budget fixtures use is not the connector the standard specifies. Section 7 of ANSI E1.11-2008 prohibits DMX512 over 3-pin XLR, even though 3-pin has become a de-facto practice across the industry. That is a connector question, not a cable question: an adaptor lead changes the plug, not the pair behind it.
What Cat5e and Cat6 are specified as
Category twisted-pair cable is specified at a nominal characteristic impedance of 100 Ω, with a ±15 Ω tolerance over its rated frequency range. That figure is a property of the construction — conductor diameter, insulation, lay length and the presence of a screen — and it is chosen for Ethernet signalling, not for a DMX bus.
So the substitution fails on the one number the bus depends on. It is not a quality problem: a well-made Cat6 cable is a better cable than a cheap DMX cable for the job Cat6 was designed for, and still the wrong impedance for a 120 Ω bus. Buying a higher category, adding a screen or using a heavier conductor does not move the impedance to 120 Ω.
We deliberately publish no distance figure for “DMX on a network pair”. Practitioners do it, and sometimes it appears to work, but any figure we printed here would be an anecdote dressed as a specification. If a project requires a standards-compliant lighting bus, the cable has to be the specified cable.
Where Cat6 is exactly the right answer: Art-Net and sACN
An Ethernet-based protocol distributes many DMX universes over one cable from the control position to breakout boxes placed near the fixtures, and those boxes then output conventional DMX512. ANSI E1.31 (sACN) and Art-Net are the two free-to-use protocols that do it, and modern control desks frequently offer RJ45 network ports instead of a row of DMX outputs for exactly this reason.
In that architecture the cable choice is straightforward: network cable from the console to the node, DMX512 cable from the node to the fixtures. Two consequences follow for the purchase order:
- The network run in a lighting position usually shares a tray, a truss or a cable path with dimmer racks, LED power supplies and motor drives. That is the environment where the shielded network constructions earn their place, which is why the LBS Ethernet range is offered as UTP, FTP, SFTP and per-pair screened SSTP rather than one unshielded type. The screening decision is set out in UTP vs FTP vs SFTP Ethernet cable explained.
- The DMX512 tail from the node to the fixtures is still a 120 Ω bus, and still needs the terminator and the daisy-chain topology described in DMX termination: 120 Ω and daisy-chain rules. Converting to Ethernet upstream does not remove the physical-layer rules downstream.
Which cable at which hop
| Hop in the rig | Port on the equipment | Cable |
|---|---|---|
| Control position: console to network switch or node | RJ45 | Cat5e / Cat6, shielded where the path shares power and dimming |
| Node or gateway to first fixture | 5-pin XLR (DMX out) | DMX512 cable, 2-core shielded twisted pair |
| Fixture to fixture along the truss | 5-pin XLR in / through | DMX512 cable, daisy-chained, terminator on the last through |
| Stage box to console rack (audio, same truss) | Multipin / fan-out | Multichannel audio snake — a separate cable from the lighting bus |
Symptoms, and what each one points at
| What you see | What it usually means |
|---|---|
| Fixtures flicker or step to unprogrammed states on a run built from network cable | The bus is being carried on a pair with the wrong characteristic impedance, and reflections are being read as data |
| One universe is dead while the rest of the rig works | Pin or pair assignment at one end, not the cable type |
| The rig behaves with one console and not another | The two consoles are presenting different port types — XLR DMX output versus RJ45 network output — and the cabling was built for one of them |
| Works on the bench, fails on site | Shield and grounding, or the cable path, rather than the console |
If the fixtures are flickering on a system that uses proper DMX512 cable, the cause is more often termination or topology than cable type; the DMX cable vs microphone cable comparison covers the other substitution that produces the same symptom.
If the building already has RJ45 sockets wired for lighting
Inheriting a venue with RJ45 lighting outlets is common, and the cable behind the socket is not always what the label suggests. Three checks before anything is ordered:
- Read the print on the jacket at a pull box or at the patch panel. It states the category and whether a screen is present.
- Confirm the pin assignment against the equipment at both ends. More than one convention is in use for putting a DMX pair onto an RJ45, and a socket wired for one convention will not match hardware built for another.
- Decide which layer the socket belongs to. A socket feeding a DMX bus and a socket feeding an Art-Net node are not interchangeable, even when both are RJ45 and both have Cat cable behind them.
What to put in a cable enquiry
Whichever layer the project is on, five answers select the cable:
- Port type at each end — 5-pin XLR DMX, 3-pin XLR, or RJ45 network.
- Which layer — a DMX512 bus, or an Ethernet link for Art-Net / sACN.
- Shield level — what the cable path shares: dimmer racks, LED power supplies, motor drives or clear routing.
- Length and packing — the drum or roll size you stock, and whether the cable is to be pre-terminated.
- Quantity and destination — for export packing and documentation.
On the DMX side LBS publishes two families with the same 2-conductor shielded construction and the same 6.3 mm matt EPVC jacket, and the difference is the shield. The single-shielded family uses a high-density OFC spiral at 85%+ coverage; the double-shielded family adds 100% coverage aluminium foil plus a tinned-copper braid and states 120 Ω on its published data sheet. On the single-shielded family the published sheet lists construction, jacket and temperature range rather than a characteristic-impedance figure — if your project documentation has to carry an impedance value, say so in the enquiry instead of assuming one.
One rule that removes the confusion
Ask which port the cable plugs into. An XLR DMX output is a 120 Ω bus and needs DMX512 cable. An RJ45 port is an Ethernet link and needs network cable, with a node at the far end to turn the frames back into a DMX bus. Every other question about “DMX over Cat6” is a variation of those two cases.
Frequently asked questions
Can you run DMX over Cat6?
Not as a DMX512 bus. The standard specifies a 120 Ω shielded twisted pair, and Cat6 is a 100 Ω construction, so the cable does not have the impedance the bus and its terminator are built around. Cat6 is the correct cable for carrying DMX universes as Ethernet traffic with Art-Net or sACN, where a gateway outputs DMX512 at the fixture end.
Is Cat6 better than DMX cable for lighting?
It is better for the job it was designed for — carrying Ethernet frames from a console to a node. It is not a substitute for DMX512 cable on a lighting bus, because the two cables are specified at different characteristic impedances. “Better cable” is not a category that exists without a specification to measure against.
What is the difference between DMX over Cat6 and Art-Net?
Art-Net is one of the protocols that carries DMX universes over Ethernet; sACN (ANSI E1.31) is the other free-to-use option. Both put the universes into network packets, so Cat5e / Cat6 is the right cable. “DMX over Cat6” in the other sense means pushing the raw bus signal onto a network pair, which is a different physical layer and outside the DMX512 specification.
Do I still need a 120 Ω terminator when a network cable is involved?
It depends which layer the terminator question is about. An Ethernet link needs no terminator at the fixture end — the network interface handles termination. A DMX512 bus still needs a 120 Ω terminator at the far end, including the DMX tail that runs from an Art-Net node to the last fixture.
What cable should I order if the console has an RJ45 lighting output?
Network cable for the run from the console to the node or gateway, shielded if that path shares a tray or truss with dimming and power equipment. Then DMX512 cable from the node to the fixtures, in the shield level the cable path requires. Both are part of one purchase list, which is why they are usually ordered together.
Standards and sources referenced
- ANSI E1.11 / E1.27-1 — DMX512 electrical specification: 120 Ω shielded twisted pair, 5-pin XLR pinout, section 7 prohibition of 3-pin XLR.
- ANSI E1.31 (sACN) and Art-Net — the two free-to-use protocols that transport DMX512 over Ethernet, with breakout boxes outputting conventional DMX512.
- Category cable specification table — Cat5e / Cat6 nominal characteristic impedance 100 Ω ±15 Ω.
- LBS product data sheets — single-shielded and double-shielded DMX512 constructions, conductor counts, jacket O.D. and temperature range as published on each product page.