How LED Control System Works and
How to Choose One
If you are buying an LED screen, most of the conversation will be about the screen: pixel pitch, brightness, size, price. The control system usually gets a single line in the quotation and no discussion at all.
That is unfortunate, because the control system determines whether your screen looks right on camera, whether you can change content without driving to site, whether the wall still looks uniform in year three, and who can help you when something stops working. It is a small part of the cost and a large part of the experience.
This guide explains what an LED control system is, what the parts do, the one decision that matters more than the rest, and the questions worth asking before you sign anything.
What Is an LED Control System?
An LED control system is the hardware and software that takes your content and turns it into what appears on the screen.
It is worth being precise here, because a lot of published material is not. The LED panels are not part of the control system. The panels are what the control system drives. The control system sits between your content source and the screen, receiving a video signal or a scheduled file, working out which pixel on which cabinet should display what, and sending that instruction out over network cable.
An LED screen without a control system displays nothing. The same set of panels driven by two different control systems can look noticeably different, refresh at different rates, and behave very differently when you want to change what is on it.
The Three Parts of an LED Display Control System
Almost every LED display control system, regardless of brand, is built from the same three components.
The sending card
The sending card is where content enters the system. It accepts a video signal, commonly over HDMI, DVI or DisplayPort, processes it, and converts it into data that LED receiving cards can read. That data then travels out over ordinary network cable, usually Cat5e or Cat6.
Sending cards come as internal cards fitted inside a computer, or as standalone boxes. The important specification is pixel capacity: each sending card can drive a maximum number of pixels. A screen larger than that capacity needs a second card, which changes the price and the cabling.
The receiving cards
Behind each cabinet sits a receiving card. It takes its share of the data from the sending card and distributes it to the driver chips on the individual modules, which switch the LEDs on and off fast enough to form an image.
Receiving cards also store the calibration data for their own cabinet, which is what keeps brightness and colour consistent from one cabinet to the next. This matters more than it sounds. It is the reason a well-configured wall reads as one screen rather than a grid of slightly different rectangles.
The software, and the two kinds people confuse
This is where most confusion happens, so it is worth separating clearly.
Configuration software sets the screen up. It maps how the cabinets are arranged, sets the refresh rate and scan mode, applies calibration, and writes all of that to the receiving cards. It is used at commissioning and rarely afterwards. Your installer uses this; you probably never will.
Content software is what you use. It schedules what plays and when, manages playlists, and pushes updates to one screen or many.
When someone says “the software is included”, ask which one. A screen can be delivered fully configured but with no content management at all, or with a content licence that quietly renews annually.
Synchronous or Asynchronous: The Decision That Matters Most
Everything above is common to all systems. This is the fork in the road, and it is the decision most buyers are never asked about.
Synchronous control
A synchronous system mirrors a source in real time. Whatever is on the connected computer, camera or switcher appears on the screen with almost no delay.
It needs that source connected and running. If the computer is switched off or the cable is pulled, the screen goes dark.
Synchronous suits anything live: stage and event screens, concerts, conferences with a presenter, live camera feeds, sports, and control rooms where operators need real-time data.
Asynchronous control
An asynchronous system stores content on the card or player itself. You upload once, set a schedule, and the screen runs on its own. Nothing needs to stay connected, and content survives a power cut.
Asynchronous suits anything scheduled: billboards, shopfronts, retail promotions, digital signage, menu boards and information displays.
Which one do you need?
The simplest test is whether your content is live or planned.
| If your screen shows | You need |
|---|---|
| A presenter, camera feed, or anything happening now | Synchronous |
| Adverts, promotions, menus or notices on a schedule | Asynchronous |
| Mostly scheduled content, occasionally a live event | Both |
That last row is common and worth knowing about. Many modern systems run asynchronously by default and switch to synchronous automatically when a live source is connected. A hotel ballroom running event branding most of the week and a live camera feed during a conference is exactly this case.
If you are quoted a synchronous-only system for a shopfront, you have been sold something that requires a computer to sit switched on behind your wall permanently.
What the Control System Actually Decides
Four things, none of which appear in a typical quotation.
Refresh rate. This is how many times per second the LEDs cycle, and it is set by the driver chips and the receiving card configuration. At 1920Hz a screen looks fine to the eye but produces scan lines and banding when filmed. At 3840Hz it films cleanly. If your screen will ever appear on camera, at an event, in a broadcast, or simply in customer photographs, this is worth specifying.
Brightness and scheduling. The control system is what allows brightness to change through the day, so an outdoor screen readable at midday is not blinding at midnight. This is also what makes automatic startup and shutdown possible.
Colour uniformity. Calibration data lives in the receiving cards. A screen calibrated at commissioning looks uniform on day one. Whether it can be recalibrated in year three depends on the system and on whether your installer left you the means to do it.
Pixel capacity. The maximum resolution a sending card can drive. Under-specify it and your screen either cannot run at full resolution or has to be split across multiple cards, which is a cost that appears late if nobody planned for it.
Common LED Control System Brands
Several manufacturers make control systems, and most Malaysian installations use one of a handful.
Novastar is the one you will encounter most often. It is widely deployed across Asia, most technicians have worked with it, and its configuration software is broadly familiar. Colorlight, Linsn and Huidu are also common, with Huidu appearing frequently in smaller asynchronous applications.
The brand matters less than three practical questions: whether the system suits how your screen will be used, whether it can be supported locally, and whether the person who installs it will hand you the documentation to move on if you ever change supplier.
A widely used platform is generally the safer choice for a permanent installation, simply because the pool of people who can service it is larger.
How to Choose an LED Control System
Work through it in this order.
1. Start with what the screen does, not with the screen. Live content points to synchronous, scheduled content to asynchronous, and a mix to a dual-mode system. Get this wrong and everything downstream is a workaround.
2. Check the pixel capacity against your actual resolution. Multiply your screen width in pixels by its height. Compare that to the sending card’s rated capacity. If it is close to the limit, ask what happens when you want to extend the screen later.
3. Specify the refresh rate if the screen will be filmed. Ask for 3840Hz rather than assuming it.
4. Decide how content will reach the screen. Over the network from an office, by someone attending site with a USB stick, or over mobile data for a site with no fixed connection. This is a practical question with cost implications and it is easier to settle before installation.
5. Ask who supports it. The installer, the manufacturer, or nobody. For a screen you expect to run for a decade, this matters more than the specification.
Eight Questions to Ask Before You Commission a Screen
Useful with any supplier, including us.
- Which control system are you fitting, and which brand?
- Is it synchronous, asynchronous, or both?
- What is the sending card’s pixel capacity, and what is my screen’s resolution?
- What refresh rate will it be configured to run at?
- Will the screen be calibrated at handover, and can it be recalibrated later?
- Is the content software licensed, and is there an ongoing cost?
- Can I update content remotely, or does someone need to attend site?
- Will I receive the configuration file and documentation?
The last one is the one nobody asks and the one that causes the most trouble later. The configuration file holds your screen’s cabinet mapping and calibration data. Without it, a different technician has to reconfigure the wall from scratch, which is slow, expensive and entirely avoidable. Ask for it at handover and store it somewhere you will find it in five years.
What Goes Wrong When the Control System Is an Afterthought
Four failures we see repeatedly.
A screen that cannot be updated without a site visit. No network access was planned, so every content change means someone drives out with a USB stick.
Banding in every photograph. The refresh rate was left at its default because nobody asked whether the screen would be filmed.
A patchy wall after two years. The screen was never calibrated properly at commissioning, or the calibration data was lost with the configuration file.
A permanently occupied computer. A synchronous system was fitted where asynchronous was needed, so a PC now sits behind the wall, switched on, forever.
None of these are faults in the panels. All of them are control system decisions made before installation.
LED Control System FAQs
What is an LED control system?
An LED control system is the hardware and software that takes your content and turns it into an image on an LED screen. It consists of a sending card that receives the video signal, receiving cards behind each cabinet that drive the modules, and software used to configure the screen and manage content. The LED panels themselves are not part of the control system; they are what it drives.
What is the difference between a sending card and a receiving card?
The sending card is where content enters the system. It takes a video signal, converts it into data the screen can read, and sends it out over network cable. Receiving cards sit behind each cabinet, take their portion of that data, and pass it to the driver chips on the modules. One sending card typically feeds many receiving cards, and the receiving cards also hold the calibration data for their own cabinet.
What is the difference between synchronous and asynchronous LED control?
A synchronous system mirrors a connected source in real time and needs that source running, so the screen goes dark if it disconnects. An asynchronous system stores content on the card and plays it to a schedule with nothing connected. Synchronous suits live content such as events and camera feeds. Asynchronous suits scheduled content such as advertising and signage. Many systems now support both.
Do I need a computer connected to my LED screen at all times?
Only with a synchronous system. Asynchronous systems hold content in their own storage and run independently, so no computer needs to remain on site. If you are being quoted a synchronous system for a shopfront or a billboard, ask why.
What refresh rate should an LED control system be set to?
If the screen will never be photographed or filmed, 1920Hz is generally adequate. If it will appear on camera at events, in broadcast, or in customer photographs, ask for 3840Hz. A low refresh rate looks fine to the eye but produces visible scan lines and banding through a camera.
Can I change the content on my LED screen remotely?
Usually yes, provided remote access was planned at installation. Content can be pushed over a local network, over the internet, or in some cases over mobile data. If no network connection was arranged, updates require someone to attend site, which is worth avoiding before it is designed in rather than after.
Is the control system software included with an LED screen?
It depends on which software, which is why the question is worth asking specifically. Configuration software is used by the installer to set the screen up. Content management software is what you use to schedule what plays. Some suppliers include both, some include neither, and some content platforms carry an annual licence. Ask which is included and whether there is a recurring cost.
What happens if the control system fails?
The screen stops displaying, but the panels are unaffected. Sending and receiving cards are replaceable components, and a failed receiving card usually affects only its own cabinet rather than the whole wall. This is why keeping your configuration file matters: with it, a replacement card can be configured and running quickly.
Talking to Us
We configure control systems on every screen we install, indoor, outdoor, transparent and signage, and we hand over the documentation so you are not dependent on us to make a change later.
If you are specifying a screen and want a straight answer on which control system suits it, we offer a free on-site consultation anywhere in Malaysia, including Sabah and Sarawak.