DMX Basics
DMX512 is the standard protocol used to control stage lighting and effects. This page explains the core concepts you need to understand before working with DMX Node.
What Is DMX512?
DMX512 (Digital Multiplex, 512 channels) is a serial communication protocol used to carry digital control data from a lighting console to lighting fixtures. It was standardized by USITT and is the most widely used protocol in stage and entertainment lighting.
A single DMX line (called a universe) carries up to 512 independent channels. Each channel holds a numeric value from 0 to 255. The console — in this case your phone running DMX Node — sends these values. The fixtures receive them and respond by adjusting intensity, color, position, or other parameters.
DMX travels over a physical cable (5-pin XLR) at 250 kbps. DMX Node does not use a physical cable directly — instead it uses Art-Net (a protocol that carries DMX data over Wi-Fi) and a hardware Art-Net node that converts the network data into a physical DMX signal. See Art-Net Protocol for details.
Channels and Values
Each DMX channel is identified by a number from 1 to 512. Every channel holds a single value from 0 a 255. What those values mean depends entirely on the fixture and its operating mode.
- A DIMMER channel: 0 = off, 255 = full brightness, 128 = approximately 50%.
- A RED channel: 0 = no red, 255 = maximum red intensity.
- A PAN channel: 0 = hard left, 128 = center, 255 = hard right (range varies by fixture).
- A STROBE channel: meaning depends on the fixture — often 0 = open, increasing value = faster strobe.
Always consult the fixture's DMX manual to find out which channel controls which parameter in each operating mode.
Start Addresses
Every fixture is assigned a start address — the DMX channel number where the fixture's channel 1 begins. The fixture then uses consecutive channels based on its channel count.
Start address calculation
The start address is set on the physical fixture (usually via DIP switches or an on-screen menu) and must match the start address configured in DMX Node. A mismatch means the wrong channels drive the fixture.
Multiple Fixtures
Multiple fixtures share the same DMX universe by using different, non-overlapping address ranges. Each fixture starts where the previous one ended.
| Fixture | Channels | Address Range |
|---|---|---|
| Fixture A | 7 | 001 – 007 |
| Fixture B | 4 | 008 – 011 |
| Fixture C | 12 | 012 – 023 |
Channel Overlap
If two fixtures are assigned overlapping address ranges, both fixtures receive the same channel values simultaneously. This is almost always unintentional and leads to unexpected behavior — for example, moving a dimmer fader causes both a PAR and a moving head to respond.
Overlap example — avoid this
Channels 014, 015, and 016 control both PAR A and Moving Head B simultaneously. Plan channel assignments to avoid this. See Channel Planning for guidance.
DMX Universe
A DMX universe is a single 512-channel space. Standard DMX provides up to 512 individual control values per universe. All fixtures in a single-universe setup share these 512 channels.
Large rigs may require more than 512 channels, which necessitates multiple universes. Free users control one universe (512 channels). Premium users can add additional output ports to an Art-Net node, each driving a separate universe.
DMX and Art-Net
Traditional DMX uses a physical 5-pin XLR cable running at RS-485 serial at 250 kbps. Art-Net is a separate protocol that wraps the same DMX channel data inside standard UDP network packets, allowing it to travel over Ethernet and Wi-Fi.
DMX512
Physical serial protocol. Runs over 5-pin XLR cable between console and fixtures.
Art-Net
Network protocol. Carries DMX data over UDP/IP. Hardware node converts it back to physical DMX.