Guide · USB DMX
USB-to-DMX interfaces and setup
The two interface types, setup, and common fixes.
What is a USB-to-DMX interface?
A small adapter that turns your computer's USB port into a DMX output. The software does the thinking; the interface converts the data into the DMX512 signal your fixtures understand. For a single universe it is the simplest and cheapest way into computer-controlled lighting.
The two types - and why it matters
Almost every affordable USB DMX interface is one of two designs. SDC supports both, with a dedicated output engine for each.
Pro-style interfaces
Enttec DMX USB Pro, Eurolite USB-DMX PRO and similar. They carry their own processor to generate the DMX signal, show up in Windows as a COM port, and keep rock-solid timing with minimal load on your PC.
Open DMX-style interfaces
Enttec Open DMX USB, Eurolite USB-DMX and similar - essentially a USB serial chip (FTDI) wired straight to a DMX plug, with the computer generating the DMX timing. Cheaper, and they work fine using the FTDI D2XX driver.
Which should you buy?
Buying new: a Pro-style interface is worth the extra money for its timing. Already own an Open DMX-style adapter? Use it - SDC drives it fine. And if you might grow past one universe later, read the Art-Net guide before buying anything.
The hardware page lists the devices we have personally tested with SDC.
Setting up USB DMX in SDC
Plug in the interface before starting SDC.
Open Settings.
Pick your device from the dropdown.
Move a fader. Your fixtures respond.
Troubleshooting
Device not in the dropdown
Open DMX-style interfaces need the FTDI D2XX driver. It usually installs automatically through Windows Update; if not, the interface manufacturer's page has it.
Device found but no output
Check the DMX cable direction, and that your fixture's DMX address matches the address in SDC.
“Device busy”
Another program - or a previous session - is holding the interface. Close other lighting software and reconnect.
SDC also includes a built-in Hardware Test that probes your USB devices and shows what it finds - useful when you are not sure Windows even sees the interface.
Questions
Do USB DMX interfaces work with any fixture?
Yes - DMX is DMX. The interface does not care whether it is driving a moving head, a dimmer pack or a fog machine.
How many channels do I get?
One USB interface outputs one DMX universe: 512 channels.
Can I use USB and Art-Net at the same time?
Yes, SDC can drive both outputs.
Plug in your interface and test it with your own rig before spending anything. SDC is free in 2-hour sessions; unlimited use is $29.99/year.
Download SDC v8.1