Spec Sheet - LT-840-6A/D4-L

Note:	Ship New Model D4-L (Base)
Availability	In Stock
Condition	Brand New

This is the Ltech D4-L, the official replacement and upgrade for the legacy LT-840-6A model. The D4-L is a professional-grade 4-channel constant voltage (CV) DMX512 decoder engineered for precise, flicker-free PWM dimming of LED lighting. It translates standard DMX512 signals into the PWM signals required to drive single color, tunable white, RGB, or RGBW LED strip lights. A key enhancement is the inclusion of RDM (Remote Device Management), which allows for bi-directional communication with a compatible DMX master controller. This feature dramatically simplifies installation by enabling remote addressing and configuration. With a robust 6A per channel output, multiple interface options (XLR-3, RJ45, Green Terminal), and a wide 5-24V DC input range, the D4-L provides the flexibility and power needed for demanding architectural, stage, and commercial lighting projects.

Front view of the D4-L DMX/RDM decoder showing ports and DIP switch.

Wiring diagram illustrating DMX console and LED strip connections.

Key Features

Advanced RDM Support

Enables bi-directional communication for remote DMX address writing and configuration, saving significant setup time on large projects.

Versatile 4-Channel Output

Provides precise 0-100% PWM dimming for RGBW, RGB, tunable white, or up to four independent single-color LED lighting zones.

High Load Capacity

Delivers a strong 6A per channel (max 24A total), capable of powering up to 576W of lighting at 24V.

Multiple DMX Interfaces

Equipped with 3-pin XLR, RJ45, and green screw terminal connections for maximum compatibility and installation flexibility.

Wide Voltage Compatibility

Operates on a broad DC 5V to 24V input range, making it suitable for virtually all constant voltage LED strip lights.

Manual & Standalone Modes

Features a 10-pin DIP switch for manual DMX addressing and includes built-in self-testing modes for easy diagnostics without a console.

Technical Highlights

Features integrated signal amplification on the green terminal DMX port, ensuring signal integrity in large installations.
Supports flexible channel configuration: 4 channels at 6A each or 3 channels at 8A each.
Equipped with short-circuit and over-current protection for enhanced system safety and longevity.
Smooth, flicker-free dimming from 0-100% suitable for on-camera applications.

Product Specifications

Parameter	Details
Model	D4-L (Replaces LT-840-6A)
Input Signal	DMX512, RDM
Input Voltage	5~24V DC
Max Current Load	6A × 4CH (Max 24A Total)
Alternate Load Config	8A × 3CH
Max Output Power	120W (5V) / 288W (12V) / 576W (24V)
Output Type	Constant Voltage (CV) PWM
DMX512 Sockets	3-pin XLR, RJ45, Green Terminal
Dimming Range	0~100%
DMX Address Setting	DIP Switch / RDM
Protections	Short circuit, Over-current
Working Temperature	-25℃ ~ 55℃
Dimensions (L×W×H)	156 × 78 × 40 mm
Package Size (L×W×H)	180 × 82 × 48 mm
Gross Weight	445g

Dimensional drawing of the D4-L decoder.

Application Scenarios

Architectural and Stage Lighting Ideal for dynamic control of building facades, cove lighting, and landscape features. Its reliable DMX decoding and high power output are perfect for professional stage productions and event lighting where precise scene control is essential.

Commercial and Hospitality Spaces Powers and controls ambient and accent lighting in restaurants, bars, retail stores, and hotels. Create immersive brand experiences and mood lighting with smooth transitions and vibrant colors, all managed through a central DMX system.

Themed Entertainment and Exhibits Provides the robust control needed for interactive museum exhibits, escape rooms, and themed attractions. The D4-L can drive multiple fixtures to create complex, synchronized lighting effects that enhance the user experience.

How to Control & Use This DMX Decoder

Mount the decoder in a dry, well-ventilated location, ensuring adequate space for heat dissipation.
Connect your constant voltage DC LED power supply to the 'Power Input' terminals. Ensure the supply voltage (5V, 12V, or 24V) matches the voltage of your LED strips.
Wire your LED strips to the 'Connection Socket' output terminals. Connect the common anode wire to 'V+' and the individual color wires (R, G, B, W) to the corresponding CH1-CH4 terminals.
Connect your DMX signal source to one of the DMX IN ports (XLR-3, RJ45, or Green Terminal). To connect multiple decoders, use a DMX cable to daisy-chain from the DMX OUT port of one decoder to the DMX IN of the next.
Set the DMX starting address. For remote setup, use an RDM-enabled master controller. For manual addressing, ensure DIP switch #10 is OFF, then use switches #1-9 to set the binary address value. This decoder occupies 4 DMX addresses.
For standalone testing without a DMX console, engage the self-testing mode by turning DIP switch #10 ON. Use switches #1-9 to select from built-in static colors and dynamic chase effects.

⚠ Precautions

This product is for use in dry, indoor locations only. If installed outdoors, it must be placed in a waterproof enclosure.
Ensure the total power consumption of your connected LED strips does not exceed the decoder's maximum output power (e.g., 576W at 24V).
Always verify that the input voltage from your power supply matches the required voltage of your LED fixtures before powering on.
For installations with more than 32 decoders or long signal lines, a DMX signal amplifier may be required.

What's in the Box

✓1x D4-L DMX/RDM 4CH CV Decoder
✓1x User Manual

⇩ Downloads & Documents

PDFD4-L

PDFLT-840-6A

Frequently Asked Questions

Q: What is the difference between the old LT-840-6A and this D4-L model?

A:The D4-L is the new, upgraded model that replaces the LT-840-6A. It adds RDM (Remote Device Management) support for easier setup and has an updated operating temperature range. We ship the D4-L for all orders of this product.

Q: What is a DMX controller for LED lights and what does RDM do?

A:A DMX decoder like the D4-L translates signals from a DMX lighting console into a format that controls the brightness and color of LED strips. RDM allows the DMX console to communicate back to the decoder, enabling remote addressing and status monitoring, which greatly simplifies installation.

Q: How do I set the DMX address manually with the DIP switches?

A:First, ensure DIP switch #10 is in the OFF position. Then, use switches #1-9 to set the starting address in binary code. Each switch has a value (1, 2, 4, 8, etc.); add the values of the switches in the ON position to get your address. Please see the dmx512 decoder manual in the Downloads section for a complete chart.

Q: Can this decoder control RGBW LED strip lights?

A:Yes, absolutely. The four channels are perfectly suited for controlling the Red, Green, Blue, and White channels of standard constant voltage RGBW LED strip lights.

Q: What kind of power supply is required for this decoder?

A:You will need a constant voltage LED power supply with an output voltage that matches your LED strips (e.g., 12V or 24V). The power supply's wattage rating must be high enough to support the total load of all connected strips.

Q: Can I test my lights with this decoder if I don't have a DMX console yet?

A:Yes. The D4-L has a built-in self-testing mode. By setting DIP switch #10 to the ON position, you can use the other switches to activate various static colors and dynamic color-changing patterns for testing and troubleshooting.

Q: How many DMX addresses does this unit use?

A:This is a 4-channel decoder, so it will occupy four consecutive DMX addresses, starting with the address you set.

4CH CV DMX-PWM Decoder LT-840-6A