ENTTEC Devices

Overview

ENTTEC is a leading manufacturer of USB-to-DMX interfaces. QLC+ provides comprehensive support for ENTTEC devices through the DMX USB plugin, including professional features like RDM (Remote Device Management) and multi-port configurations.

ENTTEC devices are supported through the DMX USB plugin. This page covers ENTTEC-specific features and configuration.

Supported Devices

ENTTEC DMX USB Pro

DMX USB Pro

Professional single-universe USB-to-DMX interfaceFeatures:

1 DMX output (512 channels)
1 DMX input (512 channels)
RDM support
Galvanic isolation
5-pin XLR connectors

Type: ProRXTX

Technical specifications:

Chipset: FTDI FT245RL
DMX Refresh Rate: Up to 44Hz (per DMX spec)
Connector: USB Type-B
Power: USB bus-powered (500mA max)

ENTTEC DMX USB Pro Mk2

DMX USB Pro Mk2

Advanced multi-port interface with MIDI supportFeatures:

2 DMX outputs (1024 channels total)
1 DMX input (512 channels)
1 MIDI output
1 MIDI input
RDM support on both outputs
Individual port control

Type: ProMk2

Port configuration:

Port 1: DMX Output (512 channels)
Port 2: DMX Output (512 channels)
Port 3: DMX Input (512 channels)
Port 4: MIDI Output
Port 5: MIDI Input

Technical specifications:

Chipset: FTDI FT232RL
DMX Refresh Rate: Up to 44Hz per port
Connector: USB Type-B
Power: USB bus-powered (500mA max)

ENTTEC Open DMX USB

Open DMX USB

Entry-level output-only interfaceFeatures:

1 DMX output (512 channels)
Output only (no input)
No RDM support
3-pin XLR connector

Type: OpenTX

Technical specifications:

Chipset: FTDI FT232RL
DMX Refresh Rate: Up to 40Hz
Connector: USB Type-B
Power: USB bus-powered (500mA max)

The Open DMX USB requires continuous DMX transmission. The plugin handles this automatically using a background thread.

Device Detection

ENTTEC devices are automatically detected by the DMX USB plugin:

Identification Process

USB Enumeration - Plugin scans for FTDI devices
Device Query - Sends label 77 (Get Widget Parameters)
Type Detection - Determines device type from response:
- DMX USB Pro: Responds with parameters, has RDM flag
- DMX USB Pro Mk2: Multiple ports, MIDI capability
- Open DMX USB: No response or minimal response

Device Serial Numbers

ENTTEC Pro devices have unique serial numbers:

static bool extractSerial();  // Read device serial number
QString m_proSerial;          // Stored serial number

Serial format: ENxxxxxxxx (e.g., EN123456)

The serial number is displayed in the device name and used for identification when multiple ENTTEC devices are connected.

DMX USB Pro Features

Opening Lines

bool open(quint32 line, bool input = false);

The Pro supports both input and output:

line = 0, input = false - Open DMX output
line = 0, input = true - Open DMX input

Configuration

The Pro can be configured with label 4 (Set Widget Parameters):

bool configureLine(ushort dmxLine, bool isMidi);

Parameters:

DMX break time
DMX Mark After Break time
DMX output rate

Writing DMX Data

bool writeUniverse(quint32 universe, quint32 output,
                   const QByteArray& data, bool dataChanged);

Data is sent using label 6 (Send DMX Packet):

Format:
  0x7E                    // Start delimiter
  0x06                    // Label (Send DMX)
  [Length LSB] [Length MSB]  // Data length
  [DMX Data...]          // 0-512 bytes
  0xE7                    // End delimiter

Receiving DMX Data

Input data arrives via label 5 (Receive DMX Packet):

int readData(QByteArray &payload, bool &isMIDI, int RDM = None);

The plugin:

Receives packet from USB
Validates packet structure
Extracts DMX data
Emits valueChanged() for changed channels

DMX USB Pro Mk2 Features

Multi-Port Support

The Mk2 has independent DMX and MIDI ports:

enum PortFlags
{
    DMX = 1 << 0,      // DMX512 protocol
    MIDI = 1 << 1,     // MIDI protocol  
    Input = 1 << 2,    // Input capability
    Output = 1 << 3    // Output capability
};

Port mapping in QLC+:

Output line 0: DMX Port 1
Output line 1: DMX Port 2
Input line 0: DMX Port 3
(MIDI ports handled by MIDI plugin)

Port Configuration

Each port can be individually configured:

bool configureLine(ushort dmxLine, bool isMidi);

For DMX ports:

dmxLine = 1 - Configure Port 1
dmxLine = 2 - Configure Port 2

For MIDI ports:

isMidi = true - Configure as MIDI

Writing to Multiple Ports

The Mk2 uses port-specific labels:

Port 1: Label 6 (Send DMX Packet)
Port 2: Label 202 (Send DMX Packet Port 2)

// The plugin automatically selects the correct label based on output line
writeUniverse(universe, 0, data, changed);  // Uses label 6
writeUniverse(universe, 1, data, changed);  // Uses label 202  

Threaded I/O

The Mk2 uses a dedicated thread for input/output:

void run() override;        // I/O thread worker
void stopThread();          // Stop I/O thread
bool m_isThreadRunning;     // Thread status flag

This enables:

Simultaneous input/output
Non-blocking DMX reception
Efficient multi-port handling

Open DMX USB Features

Continuous Transmission

Unlike the Pro, the Open DMX requires continuous DMX transmission:

class EnttecDMXUSBOpen : public QThread
{
    void run() override;  // Continuous transmission thread
    bool m_running;       // Thread control flag
};

The plugin:

Starts background thread when opened
Continuously transmits DMX at ~40Hz
Updates data buffer when writeUniverse() is called
Stops thread when closed

Timer Granularity

The Open DMX relies on system timers:

enum TimerGranularity { Unknown, Good, Bad };
TimerGranularity m_granularity;

Good: Less than 10ms timer resolution (most modern systems)
Bad: Greater than 10ms timer resolution (may affect DMX timing)

On Windows, the plugin automatically requests 1ms timer resolution for accurate DMX timing.

No Input Support

The Open DMX USB is output-only:

virtual int inputsNumber() { return 0; }

Attempting to open input will fail.

RDM Support

Both the DMX USB Pro and Pro Mk2 support RDM:

virtual bool supportRDM() { return true; }
bool sendRDMCommand(quint32 universe, quint32 line, 
                    uchar command, QVariantList params);

RDM Operations

enum RDMOperation
{
    None = 0,
    Discovery,         // Find RDM devices
    GetSetCommand     // Read/write device parameters
};

RDM Discovery

Find RDM-capable devices on the DMX line:

// Send discovery command
sendRDMCommand(universe, line, RDM_DISCOVERY, QVariantList());

// Plugin sends label 11 (RDM Discovery Request)
// Receives label 10 (RDM Discovery Response) with device UIDs

RDM Get/Set

Read or write device parameters:

QVariantList params;
params << deviceUID << parameterID << value;
sendRDMCommand(universe, line, RDM_GET, params);

Common parameters:

DMX Start Address - Set fixture address
Device Label - Device name
Lamp State - On/Off control
Pan/Tilt Invert - Axis inversion

RDM Packet Format

RDM messages use label 7 (Receive DMX on Change):

int readData(QByteArray &payload, bool &isMIDI, int RDM);

// RDM parameter indicates:
// - None: No RDM expected
// - Discovery: Expect discovery response
// - GetSetCommand: Expect parameter response

RDM requires proper DMX termination (120Ω terminator) on the line. Without it, RDM discovery may fail or be unreliable.

Driver Configuration

ENTTEC devices work with multiple driver types:

D2XX (Recommended for Windows/macOS)

Advantages:

Best performance
Lowest latency
Direct FTDI chip access

Setup:

Install FTDI D2XX drivers
Remove any VCP (Virtual COM Port) drivers
QLC+ automatically detects ENTTEC devices

libFTDI (Recommended for Linux)

Advantages:

Open source
No kernel driver conflicts
Good performance

Setup:

# Install libFTDI
sudo apt-get install libftdi1

# Add udev rule to allow non-root access
sudo nano /etc/udev/rules.d/50-enttec.rules

Udev rule:

SUBSYSTEM=="usb", ATTRS{idVendor}=="0403", ATTRS{idProduct}=="6001", MODE="0666"
SUBSYSTEM=="usb", ATTRS{idVendor}=="0403", ATTRS{idProduct}=="6015", MODE="0666"

QtSerialPort

Advantages:

No external dependencies
Cross-platform

Limitations:

Slightly higher latency
May not work with all ENTTEC devices

Troubleshooting

Device Not Detected

Check USB connection

Try different USB port
Use USB 2.0 port (some 3.0 ports have issues)
Avoid USB hubs when possible

Verify drivers (Windows)

Ensure D2XX drivers are installed
Remove VCP drivers (they conflict with D2XX)
Check Device Manager for proper device detection

Check permissions (Linux)

Add udev rule (see above)
Add user to dialout group: sudo usermod -a -G dialout $USER
Logout and login for changes to take effect

Test with ENTTEC software

Download ENTTEC’s DMX USB PRO Utility
Verify device works with official software
This confirms hardware and driver functionality

No DMX Output

Check DMX cable - Verify proper DMX cable (not XLR mic cable)
Test with simple fixture - Use a single fixture to isolate issues
Verify patching - Ensure universe is patched to ENTTEC output
Check DMX terminator - 120Ω terminator on last device
Monitor USB data - Use USB analyzer to verify data transmission

DMX Timing Issues

Check output frequency

Default is 44Hz - adjust if needed for compatibility

Verify break time

ENTTEC uses standard DMX break time (88-176μs)

Test with different fixtures

Some fixtures are sensitive to DMX timing

Update firmware

ENTTEC provides firmware updates for some devices

RDM Not Working

Verify RDM-capable fixtures - Not all DMX fixtures support RDM
Check DMX termination - RDM requires proper termination
Test one fixture at a time - Isolate problematic devices
Check cable quality - RDM is sensitive to signal quality
Verify DMX pin 4/5 wiring - Some cables don’t wire these pins

Open DMX USB Issues

The Open DMX USB is more sensitive to timing and USB issues than the Pro:

Use high-quality USB cable - Poor cables cause data corruption
Avoid USB hubs - Direct connection is most reliable
Check system timer - Windows timer resolution affects output
Update FTDI drivers - Older drivers may have issues

Performance Optimization

Output Frequency

Adjust DMX refresh rate for your needs:

virtual void setOutputFrequency(int frequency);

44Hz - Standard DMX rate (recommended)
40Hz - Slightly slower, more compatible
50Hz - Faster updates (not all fixtures support)

Windows Timer Resolution

On Windows, the plugin sets timer resolution to 1ms:

#if defined(WIN32) || defined(Q_OS_WIN)
    static uint s_windowsTimerResolution;
    bool setWindowsTimerResolution(uint resolution);
#endif

This ensures accurate DMX timing for Open DMX USB devices.

Multiple ENTTEC Devices

When using multiple ENTTEC interfaces:

Connect devices one at a time
Note serial numbers for identification
Patch universes in order of connection
Use USB ports on separate controllers if possible (reduces USB bandwidth contention)

Comparison Table

Feature	DMX USB Pro	DMX USB Pro Mk2	Open DMX USB
DMX Output	1 (512ch)	2 (1024ch)	1 (512ch)
DMX Input	1 (512ch)	1 (512ch)	None
MIDI I/O	No	Yes	No
RDM Support	Yes	Yes	No
Galvanic Isolation	Yes	Yes	No
Connector	5-pin XLR	5-pin XLR	3-pin XLR
Price Range	$$	$$$	$
Best For	Professional single-universe	Multi-universe, MIDI	Budget, learning

DMX USB Plugin

Main DMX USB plugin documentation

DMXKing Devices

DMXKing hardware support

Plugin Overview

Learn about the plugin architecture

Supported Protocols

Hardware Support

​Overview

​Supported Devices

​ENTTEC DMX USB Pro

DMX USB Pro

​ENTTEC DMX USB Pro Mk2

DMX USB Pro Mk2

​ENTTEC Open DMX USB

Open DMX USB

​Device Detection

​Identification Process

​Device Serial Numbers

​DMX USB Pro Features

​Opening Lines

​Configuration

​Writing DMX Data

​Receiving DMX Data

​DMX USB Pro Mk2 Features

​Multi-Port Support

​Port Configuration

​Writing to Multiple Ports

​Threaded I/O

​Open DMX USB Features

​Continuous Transmission

​Timer Granularity

​No Input Support

​RDM Support

​RDM Operations

​RDM Discovery

​RDM Get/Set

​RDM Packet Format

​Driver Configuration

​D2XX (Recommended for Windows/macOS)

​libFTDI (Recommended for Linux)

​QtSerialPort

​Troubleshooting

​Device Not Detected

​No DMX Output

​DMX Timing Issues

​RDM Not Working

​Open DMX USB Issues

​Performance Optimization

​Output Frequency

​Windows Timer Resolution

​Multiple ENTTEC Devices

​Comparison Table

​Related Pages

DMX USB Plugin

DMXKing Devices

Plugin Overview

Build docs developers (and LLMs) love

Overview

Supported Devices

ENTTEC DMX USB Pro

ENTTEC DMX USB Pro Mk2

ENTTEC Open DMX USB

Device Detection

Identification Process

Device Serial Numbers

DMX USB Pro Features

Opening Lines

Configuration

Writing DMX Data

Receiving DMX Data

DMX USB Pro Mk2 Features

Multi-Port Support

Port Configuration

Writing to Multiple Ports

Threaded I/O

Open DMX USB Features

Continuous Transmission

Timer Granularity

No Input Support

RDM Support

RDM Operations

RDM Discovery

RDM Get/Set

RDM Packet Format

Driver Configuration

D2XX (Recommended for Windows/macOS)

libFTDI (Recommended for Linux)

QtSerialPort

Troubleshooting

Device Not Detected

No DMX Output

DMX Timing Issues

RDM Not Working

Open DMX USB Issues

Performance Optimization

Output Frequency

Windows Timer Resolution

Multiple ENTTEC Devices

Comparison Table

Related Pages