Running DMX Over Ethernet Cable

• Running DMX Over Ethernet Cable
  • What is Ethernet
  • DMX Over Ethernet Basics
    • Power over Ethernet – PoE
    • DMX Over Ethernet Explained
• Art-Net
• sACN
  • Comparison and application of Art-Net and sACN protocols implementing DMX over Ethernet networks
  • Ethernet cables for stage lighting control protocols
  • For DMX transmission over Ethernet, the following are used:
• Understanding the Ethernet frame structure and its role in DMX transmission over IP
  • Classic and switched Ethernet for DMX
  • Converting Ethernet to DMX – supplying signals to lighting fixtures
  • Ethernet to DMX adapter – Converters
• FAQ

Despite its widespread use, DMX512 has limitations that become critical for modern lighting installations:

• No more than 32 load units can be connected to one line;
• It operates at a speed of only 250 kilobits per second;
• The maximum length of one DMX chain segment, from the controller to the last fixture, is 300 meters;
• DMX512 is unidirectional, which limits control, diagnostics, and monitoring capabilities of the fixtures;
• The DMX512 signal is susceptible to electromagnetic interference.

Today, this protocol is insufficient for controlling numerous multi-channel devices. Originally, it was designed for AC dimmer racks, where the primary, and often the only, parameter was the brightness level of the connected lamp or group of lamps. There was no need for a complex addressing system, and each dimmer channel was assigned to one DMX channel.

With the advent of LED fixtures with built-in dimming circuits and multifunctional devices capable of consuming over a hundred DMX channels for full control, the standard 512 channels are quickly exhausted with just a few fixtures. This is why there is a need to run DMX over Ethernet cable.

This is a modern solution for stage lighting control, offering unprecedented scalability, flexibility, and improved performance. By utilizing existing network infrastructures, this technology simplifies lighting management, saves time, and reduces the amount of cabling. Mastering DMX over Ethernet allows for the creation of complex and dynamic lighting designs.

Ethernet (“ether network”) is a family of technologies for packet data transmission in local area networks.

At the end of 1972, Robert Metcalfe, an American engineer and computer scientist from Xerox PARC, completed the development of a network with a speed of 3 Mbit/s. Initially called Alto Aloha Network, it was soon renamed Ethernet, and its official documentation was published on May 22, 1973. This was the first LAN in history.

In 1979, Xerox, DEC, and Intel, with Metcalfe’s participation, standardized Ethernet II, increasing the speed to 10 Mbit/s.

In 1982, the IEEE 802.3 project began for official standardization, and by the late 1990s, the technology became dominant in local area networks.

Ethernet is constantly evolving, increasing speeds. From the initial 10 Mbit/s (802.3) on “thick” and “thin” coaxial, twisted pair, and fiber optics, it transitioned to 100 Mbit/s on twisted pair and fiber optics.

Gigabit (1 Gbit/s, 802.3z, 802.3ab) is widespread, and for high demands, 5G (2.5 and 5 Gbit/s, 802.3bz) and 10G (10 Gbit/s, 802.3ae, 802.3an) have been developed.

The highest-speed 100G (40 and 100 Gbit/s, 802.3ba) uses optical cables.

All the above versions operate on a single principle, using cable connections and MAC addressing to identify the sender and receiver in the network. MAC addresses (individual, group, broadcast) can be assigned by the manufacturer or administrator.

The maximum standard segment length for twisted pair is 100 meters. With the use of specialized equipment (converters, repeaters, and splitters), the line length can be extended to hundreds or even thousands of meters.

Compared to traditional DMX, Ethernet offers:

• A larger number of devices without compromising performance;
• Flexible management from any point in the network, which is convenient for large or open venues;
• Simplified installation and multiple DMX universes over a single cable;
• Resistance to interference and stability of the lighting setup;
• Cost-effectiveness – twisted pair is often cheaper than DMX cable.

In summary, using DMX over Ethernet enhances the efficiency of the lighting system, allowing users to surpass the limitations of the basic standard, which became outdated in the early 2000s.

Power over Ethernet – PoE

Ethernet allows powering client devices over the same twisted pair cable using Power over Ethernet (PoE) technology. PoE does not affect transmission – this is a significant advantage of transmitting DMX over Ethernet.

Eliminating separate power cables simplifies device maintenance and increases electrical safety due to low-voltage power – the maximum voltage for PoE is 57V.

Professional lighting control equipment has high-voltage protection – our devices withstand up to 310V, ensuring safety even under unstable power supply conditions.

DMX Over Ethernet Explained

DMX over Ethernet works through industry-standard network protocols Art-Net and sACN, which use Ethernet as the transport medium.

Art-Net, released by Artistic License in 1998, is the de facto standard for transmitting DMX512 in IP packets. It uses UDP, ensuring minimal latency:

• Supports the Remote Device Management (RDM, ANSI E1.20) protocol, allowing for feedback and remote control of devices. Version Art-Net IV, released in 2016, supports Unicast transmission of RDM data, addressing the issues of Broadcast transmission in earlier versions;
• Allows merging of DMX512 streams based on highest priority or highest value;
• Has gained widespread support – it is used by over 500 global manufacturers of stage lighting control equipment, including Sundrax.

Each Art-Net node supports up to 1024 DMX channels (two universes) per IP address. The system can theoretically support up to 32,768 nodes with 512 DMX channels each. The actual number of universes (up to 32,768 for Art-Net IV) is limited by the network bandwidth.

Streaming ACN, or ANSI E1.31, developed by ESTA, is part of the ACN (Architecture for Control Networks) protocol family. It transmits DMX data over UDP/IP Ethernet networks. sACN uses UDP streaming to multiple recipients without acknowledgment, which is typical for streaming protocols:

• Built-in priority system allows multiple sources of DMX data to control one universe, automatically selecting data with the highest priority. This increases system resilience and reduces the likelihood of errors;
• Synchronizes DMX512 universes, ensuring simultaneous data processing by multiple receivers under one controller;
• Multicast transmission in sACN creates less network load than Broadcast transmission.

In addition, sACN surpasses Art-Net in scalability, supporting up to 65,535 DMX universes, making it more applicable for setups with a large number of lighting equipment.

Alex Chomsky
CTO Sundrax Electronics

Both protocols compete in the Ethernet environment for DMX512 transmission, using UDP packets. However, the availability of both protocols, as well as DMX converters compatible with both Art-Net and sACN, significantly expands the capabilities of technical specialists and lighting designers.

A key difference is that Art-Net has built-in support for RDM, whereas sACN requires a separate protocol for RDM data transmission. For effective operation with an sACN network, a higher level of technical knowledge in network traffic management is required, due to the use of multicast groups for each DMX universe and the need to configure IGMP Snooping on switches to prevent network overload.

For Art-Net and sACN protocols, which use Ethernet for DMX data transmission, various categories of network cables are suitable. The choice depends on speed requirements, line length, and operating conditions.

General principles:

• Twisted pair is the primary type of cable. Twisting pairs reduces crosstalk and external interference;
• The RJ-45 (8P8C) connector is the standard for twisted pair cables, widely used in office and home Ethernet networks. However, in the entertainment industry, where equipment is subjected to constant mechanical stress, vibration, dust, and moisture, the fragility and unreliability of RJ45 are mitigated by using etherCON from Neutrik – robust, protected RJ45 connectors with a round, rigid metal housing and a secure locking latch;
• Speed and performance – the higher the cable category, the greater the bandwidth it provides, which is paramount for transmitting a large number of DMX universes without delays;
• The presence of foil or braided shielding (F/UTP, U/FTP, S/FTP) increases resistance to interference – in stage lighting conditions, there may be numerous sources of electromagnetic interference, making shielding mandatory.

Multi-strand twisted pair is more flexible. It is suitable for patch cords where the cable is frequently moved (e.g., for connecting to switches or end devices in mobile installations). Single-strand twisted pair is stronger but less flexible; it is optimal for stationary installation in walls, under floors, where the cable will not be frequently moved. It provides better performance over long distances.

Cable categories – how to choose twisted pair for transmitting DMX data over Ethernet

Cat-1, Cat-2, Cat-3, Cat-4 are not intended for Art-Net/sACN due to low speed and insufficient frequency characteristics (16 Mbit/s and up to 20 MHz for Cat-4).

Cat-5 is no longer recognized by the Telecommunications Industry Association (TIA/EIA-568-B) and is not recommended for modern installations due to potential stability issues at higher speeds. Although Cat-5 can physically transmit data at 100 Mbit/s (100Base-T) and even, theoretically, at short distances, 1000 Mbit/s (1000Base-T), it was not designed and tested with the same strict tolerances for interference and crosstalk as Cat-5e or Cat-6. As a result, in practice, stability issues may arise, especially in demanding applications such as DMX transmission over Ethernet, where delays and packet loss are critical.

For DMX transmission over Ethernet, the following are used:

• Cat-5e – the minimum recommended standard for Art-Net and sACN. Recognized by TIA/EIA and tested to higher specifications, it operates at a bandwidth of 125 MHz. When using two pairs, it supports 100Base-T; with four pairs, it supports 1000Base-T (Gigabit Ethernet). The maximum segment length is 100 meters. It offers an excellent price-to-performance ratio for most standard applications, especially if the number of universes is not too large and ultra-high bandwidth is not required;
• Cat-6 – provides a significant performance improvement over Cat-5e. It is wound more tightly and often has external shielding. It operates at 250 MHz and technically supports up to 10 Gbit/s (10GBASE-T). The maximum length is 100 meters. Recommended for more demanding installations where bandwidth headroom is needed;
• Cat-6a (Augmented Category 6) – capable of supporting double the bandwidth up to 500 MHz and 10GBASE-T at distances up to 100 meters. Shielding is mandatory for Cat-6a, which virtually eliminates crosstalk but makes the cable less flexible. Recommended for professional stationary installations where maximum performance and interference protection are required. Cat-6a is fully backward compatible with Cat-5 and Cat-6. However, in any cable line, the data transmission speed will always be limited by the speed of the lowest category cable or connector installed in that line.

Cat-7 (class F according to ISO/IEC 11801) is a proprietary standard that differs from common Ethernet categories in that it traditionally does not use the RJ-45 connector. It is designed for operation at frequencies up to 600 MHz. Despite its high performance, Cat-7 is often redundant for most standard Art-Net/sACN applications unless there are extremely specific requirements for frequency characteristics. Category 7 cables are not a universally accepted standard, and their performance can generally be achieved with the widely supported Cat-6a.

Cat-8 is intended for data centers and very short distances (up to 30 meters for 25GBASE-T/40GBASE-T). Technically, it can be used, but its capabilities are highly redundant, and the cost and length limitations make it impractical for most Art-Net/sACN installations.

In conclusion, for reliable operation of DMX over Ethernet systems (Art-Net, sACN) in professional settings, it is recommended to use cables of category Cat-5e and above. For mission-critical and large-scale projects, shielded Cat-6 or Cat-6a cables (F/UTP, S/FTP) are preferred.

The data unit of the Ethernet protocol is called a frame, which forms the foundation of network transmission. A device forms this frame, which is then converted by its network adapter into the corresponding electrical or optical signal. This signal is then directed to a switch or router within the local network. Here, the recipient’s MAC address is checked. The end recipient device accepts the frame, performs an integrity check using the checksum (FCS), and proceeds to process the data contained within it.

An Ethernet frame consists of a header, payload, and trailer. The header (14 bytes) contains the source and destination addresses, as well as information about the type or length of the payload. The payload is the transmitted data, and the trailer includes a checksum for integrity verification.

Among various frame formats, Ethernet II is the most common. It has a fixed 14-byte header and a variable payload of up to 1500 bytes, where the type field indicates the payload protocol (IPv4, IPv6, or ARP).

Additionally, there are IEEE 802.3 standards (14-byte header, up to 1492 bytes payload, length field, and 4-byte CRC trailer), as well as its extensions IEEE 802.2 (16-byte header, up to 1490 bytes payload, DSAP/SSAP fields) and IEEE 802.2 SNAP (22-byte header, up to 1484 bytes payload, with OUI and type fields in the trailer). The differences between formats lie in the size and content of the headers/trailers, as well as the method of determining the payload protocol.

Ethernet standards regulate the physical layer (wired connections and electrical signals) and the data link layer of the OSI model (frame format and media access protocols). Meanwhile, Art-Net and sACN protocols operate at higher levels of the network model – transport and application layers, using IP (IPv4 or IPv6) and UDP for data transmission. The corresponding IP/UDP packets with Art-Net or sACN information are then encapsulated into one of the Ethernet frame formats for subsequent physical transmission over the network.

Classic Ethernet used hubs, creating a physical “star” topology with a logical “bus” topology. In this model, the LLC and MAC sublayers were present together, and the CSMA/CD access method controlled collisions (frame overlaps). However, classic Ethernet becomes inoperable at loads around 50% due to frequent collisions. This makes it undesirable for transmitting DMX data via Art-Net/sACN, as data sensitive to delays and packet loss would lead to unpredictable operation of lighting fixtures. Large networks with hundreds or thousands of nodes cannot be reliably built based on a single shared medium of classic Ethernet technology, even with high-speed Gigabit.

Today, the only acceptable standard for professional lighting control systems (as well as for 10G and above) is switched Ethernet with dedicated bandwidth for each connection. Instead of a hub, a switch is used, providing direct port-to-port connections using point-to-point technology. Frames are directed to the recipient through a transparent bridge algorithm, completely eliminating collisions and significantly increasing network efficiency.

Although Art-Net and sACN protocols are formally compatible with classic Ethernet with a shared medium, for reliable and efficient operation in stage lighting, they necessarily use switching.

Art-Net and sACN protocols allow transmitting thousands of DMX universes over a single Ethernet cable, saving time and resources in installations. This requires a DMX-Ethernet node (converter) that converts Art-Net or sACN to standard DMX. Modern lighting control systems use Ethernet as the transport medium, which requires separate protocols; however, lighting fixtures work with DMX512. Art-Net to DMX and sACN to DMX converters translate digital Ethernet data into the DMX signal understandable by lighting fixtures.

All Sundrax converters are distinguished by high performance, reliability, and ease of use. Professional connectors, no moving parts, efficient cooling, and optimized architecture ensure instant response and long service life. Built-in Watchdog and redundancy capabilities guarantee uninterrupted operation, while an intuitive interface and support for ArtGate Setting / ARISTO simplify configuration.

ArtGate is a line of intelligent DMX-Ethernet converters by Sundrax with data merging and redundancy functions. They support daisy-chaining for power, DMX, and Ethernet, allowing easy system scaling. All XLR ports are bidirectional for flexible configuration.

The ArtGate family includes several models:

• Pro – a full-featured converter with 4 or 8 DMX ports (optionally with etherCON), 2 Ethernet ports for expansion/redundancy/cascading, 2 trigger ports, power via PowerCON, and a sturdy metal housing weighing 1.2 kg;
• Solid – a vandal-resistant converter with 2 or 4 DMX ports (XLR M or F) and 2 Ethernet ports, weighing 1.2 kg;
• DIN – a compact converter for DIN rail mounting with 4 or 8 DMX ports (terminal blocks), 2 trigger ports, and Ethernet connectors, weighing 0.85 kg and occupying 12 modules;
• Arma – a model with 2 or 4 DMX ports (terminal blocks), 2 Ethernet ports, and 2 professional Ethernet connectors;
• Compact – a miniature converter with 2 DMX ports, powered by PoE through 1 Ethernet port, weighing only 100 grams, ideal for installation in standard 10-centimeter wall boxes;
• Board – a powerful converter in the form of a board weighing 50 grams, equipped with 1 DMX connector, 1 Ethernet port, and 1 Ethernet connector (optionally etherCON).

How to output DMX signal over Ethernet

Setting up DMX over Ethernet may seem complex, but breaking it down into smaller steps makes it manageable. Here’s a simple guide:

1. Gather your equipment – you’ll need Ethernet nodes, a network switch, Ethernet cables, and DMX-compatible lighting fixtures. Make sure your nodes are compatible with your chosen protocol (Art-Net or sACN)
2. Connect the nodes – plug your Ethernet nodes into the network switch using Ethernet cables. These nodes will convert DMX signals to Ethernet and vice versa
3. Set up the network – assign IP addresses to each node and configure the network for seamless communication. Ensure all devices are on the same subnet to avoid connectivity issues
4. Connect to lighting fixtures – use DMX cables to connect your lighting fixtures to the Ethernet nodes. This setup allows the nodes to control the lights over the network
5. Configure control software – install DMX control software on your computer. This software will send commands over the Ethernet network to your lighting fixtures. Set up the software to match your network settings
6. Test the setup – before the event, run tests to ensure everything works correctly. Check each fixture to make sure it responds properly to commands from the control software

Sources:

• https://www.linkedin.com/advice/1/how-do-you-compare-contrast-ethernet-frame
• https://www.sundrax.com/
• https://www.linkedin.com/in/aleksandar-nikolic-203375312/
• https://www.linkedin.com/in/alex-chomsky-2a37b6311/
• https://en.wikipedia.org/wiki/User_Datagram_Protocol
• https://en.wikipedia.org/wiki/Ethernet