LED Display Control Systems: Sending Cards, Receiving Cards & Video Processors — Complete Technical Guide (2026)

When a buyer specifies an LED display, they almost always focus on the panels themselves — pixel pitch, brightness, cabinet size, IP rating. And that makes sense. The panels are what people see. But the real difference between a display that delivers stunning, reliable performance and one that creates constant headaches is invisible: the control system.

The sending cards, receiving cards, and video processors that drive an LED wall determine everything from refresh rate and color accuracy to system stability and long-term maintenance costs. Yet most buyers — and even many AV integrators — treat the control system as an afterthought.

This guide provides a complete technical breakdown of LED display control systems. Whether you are an AV integrator, a project manager at a systems integration firm, or a buyer evaluating LED wall proposals, understanding the control layer will help you make a better-informed purchasing decision and avoid costly mistakes.

What Is an LED Display Control System?

An LED display control system is the set of electronic components that receive a video signal from a source (computer, media player, HDMI/SDI input), process it, distribute it across the display cabinets, and drive each individual LED to produce the correct color and brightness at the right time.

A complete control system consists of three hardware layers:

1. Video Processor (also called a video controller or switcher) — The front-end device that accepts multiple input sources, scales the image to the LED wall's native resolution, handles PiP (picture-in-picture), and outputs a signal to the sending cards.
2. Sending Card (also called a HUB card or transmitter card) — A PCIe card or standalone box that receives the processed signal, encodes it into a data stream, and transmits it to the receiving cards over Ethernet or fiber optic cables.
3. Receiving Card (also called a receiver card or scan board) — A small board mounted inside each LED cabinet that receives the data stream, decodes it, and drives the individual driver ICs to control each LED pixel on the module.

Most manufacturers (NovaStar, Colorlight, Brompton) produce all three layers as an integrated ecosystem, though sending and receiving cards are typically sold together as a matched pair while video processors can often be mixed across brands with standard interfaces.

The Signal Chain: From Source to Pixel

Understanding the signal path helps diagnose problems and make better spec decisions. Here is the complete chain:

Each link in this chain introduces latency, data compression, and potential failure points. A high-quality control system minimizes latency (ideally under 1 frame at 60Hz), uses lossless or near-lossless encoding, and includes redundancy features at every level.

Critical spec for buyers: The total system latency from HDMI input to pixel illumination should not exceed 1-2 frames (16-33ms at 60Hz) for standard use. For live broadcast or interactive applications, sub-frame latency (under 8ms) is required, which typically necessitates a Brompton or high-end NovaStar system with dedicated processing hardware.

Video Processors: The Brain of the Wall

The video processor is the most important single component in the control chain. It handles several critical functions that directly affect image quality and usability:

Input Handling & Switching

Video processors accept multiple input formats and resolutions. Typical inputs include HDMI 2.0/2.1, DisplayPort, 12G-SDI, DVI, and VGA. The processor must handle seamless switching between sources — meaning no black screen, no signal glitch when the operator switches from a laptop feed to a live camera. This is a standard feature on mid-range and above processors from all three major brands.

Resolution Scaling

An LED wall almost never matches a standard video resolution. A P1.9 wall measuring 3.84m × 2.16m at 1920×1080 physical pixels requires the processor to scale the input to exactly 1920×1080. For larger walls with non-standard resolutions (e.g., 2688×1512 for a P1.5 wall), the processor's scaling engine must handle non-square pixel mapping and fractional scaling without introducing artifacts or blurring.

NovaStar's MCTRL series supports up to 4K input with pixel-level mapping. Colorlight's S2 and Z6 offer similar capabilities. Brompton's Tessera SX40 can handle 4K60 input with ultra-low latency and feeds up to 8 million pixels via fiber — enough for a massive stadium display.

Multi-Layer & PiP Support

For complex installations like control rooms, broadcast studios, or event staging, the processor must support Picture-in-Picture (PiP) and multi-layer compositing — displaying multiple input sources on different areas of the LED wall simultaneously. Higher-end processors from all three brands support 2-4 layers, while dedicated broadcast-grade processors (like NovaStar's VX series) support 4-8 layers with independent scaling and positioning per layer.

Sending Cards (HUB Cards): Signal Distribution

The sending card sits between the video processor and the receiving cards. Its primary job is to encode the processed video signal into a data format that can be transmitted over standard Ethernet cabling to the individual LED cabinets.

Key specs to understand:

• Maximum load capacity — How many pixels can a single sending card drive? NovaStar's MCTRL660 supports up to 2.3 million pixels (1920×1200). The MCTRL4K supports up to 4.2 million pixels (3840×2160). Colorlight's S2 supports 1.3 million pixels per Ethernet port, with 4 ports for a total of 5.2 million pixels.
• Number of Ethernet outputs — Each port on a sending card connects to a daisy chain of receiving cards. More ports = more cabinets driven = larger walls supported. Common configurations: 2-port (small walls under 5 cabinets), 4-port (medium walls), 6-8 port (large walls).
• Max cable distance — Standard Ethernet (CAT5e/CAT6) supports up to 100 meters between the sending card and the first receiving card. For longer runs, fiber optic converters are required, or the sending card must support direct fiber output (e.g., NovaStar MCTRL4K with SFP+ fiber module).
• Redundant backup — High-reliability installations require dual sending cards in active-passive or active-active configuration. If the primary card fails, the backup takes over without signal loss. This is standard for broadcast, control room, and mission-critical digital signage.

Most modern sending cards use NovaLCT (NovaStar), LEDVision (Colorlight), or Tessera (Brompton) software for screen configuration — including cabinet layout mapping, brightness calibration, color temperature adjustment, and module scanning parameters.

Receiving Cards: Precision Pixel Control

Receiving cards are the most numerous component in any LED display system — typically one per cabinet (or one per two cabinets for budget configurations). These small boards receive the Ethernet data stream from the sending card and convert it into the precise drive signals that control each LED.

Critical performance parameters:

• Scan mode — Determines how many rows of pixels are refreshed simultaneously. 1/4 scan (e.g., 16 rows out of 64) is common for indoor P2-P4 displays. 1/8 or 1/16 scan is typical for outdoor displays with larger pixel pitches. Static (1/1 scan) is used for high-end fine pitch displays and provides the best image quality but requires the most receiving cards per cabinet.
• Maximum resolution per card — A typical receiving card can drive up to 512×256 pixels or 256×256 pixels depending on the scan rate and module design. This determines how many receiving cards you need per cabinet.
• Bit depth / grayscale — Most commercial receiving cards support 14-bit to 16-bit grayscale processing, meaning each RGB channel can display 16,384 to 65,536 levels of brightness. Combined, this produces 68 billion to 281 trillion colors. Higher bit depth = smoother color gradients and no visible color banding in low-brightness content.
• Refresh rate support — The receiving card and driver IC combination determines the maximum refresh rate. Standard: 1920Hz. High-end: 3840Hz. Broadcast: 7680Hz (supported by Brompton and select NovaStar/Colorlight cards). Higher refresh rates eliminate visible flicker on camera — critical for broadcast applications.
• Daisy chain port — Receiving cards have input and output Ethernet ports, allowing them to be daisy-chained. Each card receives data, processes its own cabinet's pixels, and passes the remaining data downstream to the next cabinet. This reduces cabling complexity but introduces a failure point: if one receiving card fails, all downstream cabinets lose signal — unless the system is wired in a loop-back (star) topology.

Pro tip for buyers: Always ask your LED manufacturer whether the receiving cards support loop-back (redundant) cabling. In a loop-back configuration, the last cabinet in the chain feeds back to the sending card. If any Ethernet cable in the chain breaks, the signal routes the other direction. This is a low-cost redundancy that dramatically increases system reliability and is standard on NovaStar A5s/A8s receiving cards and Colorlight 5A series.

NovaStar Ecosystem Overview

NovaStar (a subsidiary of Unilumin) is the dominant control system brand in the LED display industry, with an estimated 60-70% global market share for sending and receiving cards. Their ecosystem is comprehensive and spans everything from budget indoor displays to flagship outdoor stadium walls.

Popular NovaStar Products

Software: NovaLCT

NovaLCT is NovaStar's configuration and calibration software. It supports:

• Screen wiring topology mapping — drag-and-drop cabinet arrangement
• Brightness and color temperature global/zone adjustment
• Module-level calibration data upload and management
• Gamma adjustment (default 2.8 for indoor, 2.2 for outdoor)
• Automatic flat cable detection for module mapping
• Real-time monitoring of temperature, voltage, and fan status

Strengths: Widest global distribution, best spare parts availability, comprehensive product range for every application, strong software ecosystem, competitive pricing.

Weaknesses: Software UI can feel dated compared to Brompton. HDR support is less mature. Customer support response times vary by region.

Colorlight Ecosystem Overview

Colorlight is NovaStar's primary competitor in the mid-range control system market. Originally known for LED display receiving cards, Colorlight has expanded into a full ecosystem including video processors and sending cards. They hold roughly 15-25% market share globally and are particularly popular in the rental and staging market for their rugged hardware and competitive pricing.

Popular Colorlight Products

Software: LEDVision

LEDVision is Colorlight's configuration platform. Compared to NovaLCT, it offers:

• Simpler UI with faster learning curve for technicians
• Support for multi-unit cascade calibration
• Real-time cabinet display status monitoring
• Mobile app for quick brightness/color adjustments on site

Strengths: Competitive pricing, strong rental market presence, rugged build quality for touring applications, good Colorlight calibration technology, fast new product release cycle.

Weaknesses: Smaller ecosystem than NovaStar, less third-party software integration, fewer spare parts distributors in non-Asian markets, lower maximum pixel load per card compared to NovaStar equivalents.

Brompton Technology: The High-End Standard

Brompton Technology is the premium control system brand, widely considered the gold standard for high-end rental, broadcast, and virtual production applications. Founded in the UK, Brompton has built its reputation on image quality, reliability, and industry-first features.

Brompton systems are priced significantly higher than NovaStar or Colorlight — typically 2-3x the cost of equivalent NovaStar hardware — but for applications where image quality is critical, the investment is justified.

Key Brompton Products

What Makes Brompton Different

• True 16-bit processing — Complete 16-bit pipeline from input to pixel. NovaStar and Colorlight also claim 16-bit but apply compression in the sending card that can reduce effective bit depth. Brompton maintains full 16-bit throughout.
• Chromatic calibration — Not just brightness/color temperature, but per-pixel chromaticity (color point) calibration. Every individual LED on the wall is measured and adjusted to match a target color gamut, producing uniform color across the entire display.
• Ultra-low latency — Sub-frame latency (under 0.5 frames) with Tessera systems. This is critical for live events where audio and video must stay in sync, and for virtual production where LED walls interact with camera tracking systems.
• 5760Hz refresh rate — The Tessera R2 receiving card supports up to 5760Hz refresh rate, eliminating any visible flicker on high-speed cameras. Combined with 3.8V driver ICs, this provides buttery-smooth camera recording at any shutter speed.
• Color calibration with spectroradiometer — Brompton's calibration process uses a Konica Minolta CA-410 or similar spectroradiometer, measuring color at the LED level for broadcast-grade DCI-P3 or Rec.709 color space matching.
• HDR support — Full HDR10 and HLG support with peak brightness mapping. The Tessera platform supports HDR EOTF (PQ curve and HLG) for true high dynamic range content playback.

Strengths: Unmatched image quality, best-in-class calibration, industry-standard for virtual production (used on major film/TV sets), superior customer support, robust hardware designed for touring.

Weaknesses: 2-3x the cost of NovaStar, receiving cards require static scan (more cards per cabinet = higher cabinet cost), longer lead times, fewer technicians trained on Brompton compared to NovaStar, limited product availability in some markets.

NovaStar vs Colorlight vs Brompton: Head-to-Head

Calibration Capabilities: Why It Matters for Your Project

Calibration is the single most important factor determining whether an LED wall looks professionally installed or amateurish. Here is how the three ecosystems compare:

Brightness Calibration (All Brands)

All three systems support module-level brightness calibration. Each LED module is scanned in a darkroom environment at the factory, the brightness of each pixel is measured, and a correction coefficient is stored on the receiving card. When the display runs, the receiving card applies these coefficients to ensure uniform brightness across the entire wall.

NovaStar and Colorlight typically perform brightness-only calibration at the module level. This is sufficient for most commercial applications — the wall will appear uniform to the naked eye.

Chromatic Calibration (Brompton, select NovaStar)

Chromatic calibration adjusts not just brightness but the exact color point of each LED. Since individual LEDs within the same batch can vary noticeably in their emitted color (especially red LEDs), chromatic calibration ensures that every pixel on the wall displays the same color when driven with the same RGB values.

Brompton's Chromatic Calibration is the industry benchmark. It uses a spectroradiometer to measure the CIE x, y coordinates of each LED, then adjusts the drive signal to match a target color space (Rec.709, DCI-P3, or Rec.2020). The result is color-accurate across the entire wall — critical for broadcast, virtual production, and museum/trade show environments where content is designed to exact color standards.

NovaStar's more recent HDR processors and A8s+ receiving cards have introduced limited chromatic calibration support, but it is not yet at the same fidelity as Brompton's system.

When Do You Need Chromatic Calibration?

• Broadcast studios — Cameras pick up any color variation. Chromatic calibration is essential.
• Virtual production / XR — The LED wall serves as a camera background. Color accuracy determines how well on-set elements match the virtual environment.
• High-end retail / museum — Color-critical product displays, artwork reproduction, or brand color consistency.
• Any P1.2 or finer pitch wall — Smaller pixels amplify color variation issues because the viewer is closer.

How to Choose the Right Control System for Your Project

Here is a decision framework based on application type:

Indoor Commercial (Conference Room, Lobby, Retail, Corporate Signage)

Recommended: NovaStar MCTRL660 + A5s/A8s receiving cards

For standard indoor applications, NovaStar offers the best balance of price, performance, and availability. The MCTRL660 drives up to 2.3 million pixels — enough for a 110-inch P1.5 wall. A5s receiving cards support 3840Hz refresh rate and 14-bit grayscale. Most LED manufacturers stock NovaStar cards as standard, so spare parts and support are easy to source.

Budget option: Colorlight S2 + HD-R212 receiving cards — roughly 15-20% less expensive than equivalent NovaStar.

Outdoor / Stadium (Billboard, Sports Venue, Building Wrap)

Recommended: NovaStar MCTRL4K + A8s receiving cards

Large outdoor walls require high pixel counts (often 4K+ native resolution), high brightness output (5000-10000 nits), and long cable runs. NovaStar's MCTRL4K supports fiber optic direct output for runs up to 10km. A8s receiving cards handle the high-duty-cycle requirements of outdoor operation (temperature range -20°C to +80°C). Colorlight S4 + 5A-75E cards are a viable alternative for smaller outdoor walls.

Rental & Event Staging

Recommended: Colorlight Z6 + 5A series receiving cards

Rental companies typically prefer Colorlight for its rugged hardware, fast setup with LEDVision's simplified configuration, and lower replacement cost when equipment gets damaged in transit. The Z6 processor supports quick source switching between cameras, presentations, and playback servers. For high-end rental work where image quality is paramount (e.g., product launches, concerts with camera IMAG), Brompton Tessera is the market standard.

Broadcast Studio & Virtual Production

Recommended: Brompton Tessera SX40 + R2 receiving cards

There is no substitute for Brompton in broadcast and virtual production. The chromatic calibration, true 16-bit processing, sub-frame latency, and 5760Hz refresh rate are not optional features — they are requirements for camera-facing LED walls. The higher hardware cost is typically a small fraction of the total studio build budget, and the image quality difference is immediately visible on camera.

NovaStar's VX4S with HDR processor can serve as a cost-effective alternative for live news studio sets where the camera distance is greater than 3 meters and the wall uses fine pitch (P1.2 or smaller).

Control Room / Command Center

Recommended: NovaStar VX4S/VX6S + MCTRL4K + A5s/A8s

Control rooms require multi-source PiP/PoP display, ultra-reliable operation (often 24/7/365), and remote monitoring. NovaStar's ecosystem excels here with the VX processor series supporting up to 8 input sources and 4 independent output layers. Remote monitoring via NovaLCT's network management feature allows operators to check cabinet temperature, voltage, and fan status from a central console. Dual-redundant sending cards are standard in control room installations.

Frequently Asked Questions

Can I mix NovaStar sending cards with Colorlight receiving cards?

Generally, no. Sending and receiving cards from different brands use incompatible data encoding protocols. You must use matched brand pairs. The one exception is the video processor layer — many NovaStar and Colorlight processors output standard HDMI/SDI signals that can feed any brand's sending card.

What Ethernet cable do I need between sending and receiving cards?

Standard CAT5e or CAT6 solid-core shielded Ethernet cable. For maximum reliability, use outdoor-rated (UV-protected) CAT6. Maximum cable length between the sending card and the first receiving card is 100 meters. Beyond that, use a fiber optic converter or a switch with fiber uplink.

How many cabinets can one sending card Ethernet port drive?

It depends on the cabinet resolution and the receiving card's load capacity. A typical P2.9 indoor cabinet at 128×128 pixels per module (2 modules per cabinet = 256×128) can run 16-24 cabinets per Ethernet port. A P1.5 fine pitch cabinet at 256×256 pixels per module needs more bandwidth and typically supports 8-12 cabinets per port. Always consult the sending card's data sheet for the maximum pixel per port specification and divide by your cabinet's pixel count.

What is the difference between 1920Hz and 3840Hz refresh rate?

Refresh rate is how many times per second the display redraws the image. 1920Hz (19,200 times per second — note that LED display refresh rates are measured in Hz and represent the PWM frequency, not the frame redraw rate) is sufficient for most indoor and outdoor applications. 3840Hz eliminates flicker visible to sensitive viewers and is required for camera recording at standard shutter speeds. 5760Hz+ is needed for high-speed camera recording (slow-motion shots) and is typically specified for broadcast and virtual production.

Can the video processor upgrade a 1080p LED wall to accept 4K input?

Yes — but with a caveat. The video processor can accept a 4K input and downscale it to the wall's native 1080p resolution. This gives you a sharper input source but does not increase the wall's physical resolution. To display true 4K, the LED wall itself must have 4K or higher physical pixel resolution (approximately 8+ million pixels). For P1.2 fine pitch, this means a wall roughly 2.4m × 4.2m or larger.

How do I know if my LED wall supports HDR?

HDR requires three things: (1) a video processor that supports HDR10/HLG metadata passthrough, (2) receiving cards with 16-bit processing capability, and (3) LED modules with sufficient peak brightness (1000+ nits for indoor, 5000+ nits for outdoor) and wide color gamut. Check with your manufacturer that all three layers are HDR-compatible. Brompton Tessera systems support true HDR. NovaStar's HDR processor and A8s+ receiving cards offer partial HDR support with PQ curve mapping.

Summary: Building a Reliable Signal Chain

The LED display control system is the invisible architecture that turns a collection of cabinets into a single, unified display. Choosing the right system — and configuring it correctly — is as important as choosing the right pixel pitch or brightness specification.

Key takeaways:

• NovaStar is the safe default for 65% of projects — widely available, well-supported, and cost-effective for commercial, outdoor, and control room applications.
• Colorlight offers better value for rental and event staging with rugged hardware and competitive pricing.
• Brompton is the professional standard for broadcast, virtual production, and any application where image quality cannot be compromised.
• Calibration quality varies significantly between systems — chromatic (per-pixel color) calibration is essential for camera-facing applications and available only on Brompton and select NovaStar configurations.
• Redundancy matters — specify dual sending cards and loop-back cabling for mission-critical installations.
• Don't skimp on the processor — buying one tier above your current needs saves significant upgrade cost and downtime later.

When evaluating LED display proposals from manufacturers, always ask what control system is included. A proposal that quotes NovaStar or Colorlight is standard and fine for most applications. A proposal that includes Brompton signals that the supplier understands high-end requirements. If the proposal does not specify the control system brand at all — ask why.

At MAXV Display, we configure every LED wall with the control system that matches the application. Our standard commercial walls use NovaStar MCTRL660 with A5s/A8s receiving cards. For broadcast and virtual production projects, we offer Brompton Tessera integration. Contact our technical team to discuss the right control system for your next project.