Lighting and control

ENTTEC Open DMX USB

Configure Open DMX USB 70303 with compatible software; check USB detection, universe output, fixture profile and stability before the event.

Ask GLMedia about renting ENTTEC Open DMX USB for your event. Availability and configuration are subject to confirmation.

Model and purpose

Manufacturer: ENTTEC
Model: ENTTEC Open DMX USB
Model: Open DMX USB; 70303
Output: 1 universe; up to 512 channels
Connections: USB 2.0 Type-B; 5-pin XLR
Power: 5 V DC over USB; 1.5 W

Interface for sending DMX from a computer to lighting fixtures. A compatible application must remain running: signal processing and timing depend on the host computer. This is not the DMX USB Pro variant.

Prepare your rental inquiry

Date, city, venue and setup, event and pickup schedule.
Intended use, area dimensions and equipment already supplied by the venue or production.
Intended computer, operating system and lighting software.
Connectors, required output and compatible drivers to be confirmed.

Specify equipment only or whether setup, programming, operation and strike are also needed. Scope is confirmed in the proposal.

You do not need a final equipment list: tell us the result you want and the part you need help with. Availability and scope are confirmed in the proposal.

Features and connections

The female XLR is output only; it does not receive DMX or provide RDM. It neither plays scenes independently nor supports firmware updates.

It has no electrical isolation or LED indicators. A missing status light does not establish that it is unpowered; check detection in the operating system and application.

Prepare the system

Verify application, version and operating-system compatibility. EMU, ELM and Pro-Manager do not support this model; do not use Pro instructions.
Connect USB and a test fixture using DMX cable. In QLC+, open Inputs/Outputs, locate DMX USB and select Output for the chosen universe. If a device type must be selected, use Open TX.
In Simple Desk, move the channels matching the fixture profile and address. Check dimmer and shutter where applicable before building scenes.

Questions and troubleshooting

Does the application fail to find the interface?

Distinguish operating-system detection from program access.

Close other lighting applications: only one program can access the interface at a time. Reconnect during a controlled test, away from an active show.
Check whether the operating system detects USB. Windows may list USB Serial Converter or USB Serial Device; it does not need to show a fixture name.
Try another port and a USB cable shorter than 1 m. If the system sees it but the application does not, check compatibility and that software’s platform-specific driver guide before changing drivers.

Is it connected but producing no light?

USB detection does not automatically enable a universe.

Check Output and the assigned universe in Inputs/Outputs. Do not select Pro mode or an RX input.
Check fixture DMX address and mode, power, cabling and line termination. A fixture may need dimmer and shutter as well as color channels.
Test Simple Desk with a single known fixture. The interface transports channels; do not add its model to the patch as a fixture.

Do lights flicker when other applications are used?

Timing depends on the computer; the DMX line can also cause this symptom.

Save the project and compare a simple scene without competing applications or heavy tasks. Record version, load and when flicker occurs.
Check cables and test a short known line. If the QLC+ version allows output-frequency adjustment, try gradual reductions and check fixture response.
Do not treat a frequency reported by another user as a guaranteed fix. If the issue persists, discuss an interface with onboard processing and isolation with the responsible technician.

Quick reference

Staged diagnosis: USB detection and DMX output are separate checks.
Stage	Check	Does not establish
Operating system	USB device visible	Application compatibility
Application	Output and universe	Fixture address
DMX	Test response	Stability under load

Precautions

Indoor IP20 use, ambient 0–50 °C without condensation. Do not expose to rain or moisture.
Do not open the enclosure or connect DMX GND to electrical earth. ENTTEC recommends a splitter for added protection and flexibility; verify isolation in the chosen device.
Do not replace drivers using a generic recipe: USB access varies with software and operating system. Record the existing state before changes.

Terms on this page

DMX: A data protocol controlling lighting functions; each model defines what its channels mean.
RDM: Management communication for querying or configuring compatible equipment over a compatible path.
Patch: Assignment of fixture, profile, address and universe in the control system.
Shutter: A fixture function opening or closing light output; distinct from the camera shutter.

Documentation and sources

Accessed: 2026-10-22. Official July2025 datasheet and ENTTEC2026 guides; QLC+4 plugin reference. Proposed adjustments and checks have not been physically tested by GLMedia; verify versions.