Inside every cabinet of an LED screen there is a small but decisive part: the LED receiving card, the electronic component that receives the already-processed signal and turns it into the exact instruction that lights up every pixel —colour, brightness and refresh rate— on the LED modules. At LEDLEMON we design, manufacture and install LED screens for indoor, outdoor and rental use, and the receiving card is one of the parts that most affects the final image quality, even though the client never actually sees it.

In this article we explain what an LED receiving card is, where it fits in the complete signal chain —from the content source to the LED module— and why choosing it determines the maximum resolution, the refresh rate and the reliability of the whole screen.

What an LED receiving card is

The LED receiving card —the name used internationally for this component— is the electronic board installed inside every cabinet that receives the already-processed video signal and distributes it to the LED modules in front of it. It doesn't generate or edit content: its job is to convert the digital signal it receives into the electrical instruction that lights each diode with the correct colour, brightness and timing, thousands of times per second.

Together with the LED module and the chassis, it is one of the parts that let an LED cabinet work as a self-contained unit within the screen: each cabinet receives its portion of the image and displays it in sync with the rest thanks to its own receiving card.

The complete signal chain: from source to LED module

To understand why the receiving card matters, it helps to see the whole journey the image makes before it reaches the LED:

  • Content source: the media player, the PC or the video signal (HDMI, SDI) that is to be displayed.
  • Video processor (sending card): converts that signal into the format LED screens understand and distributes it across the screen's different physical zones.
  • Network cable or fibre optic: carries the already-processed signal from the sending card to each cabinet; Ethernet cable over short distances, fibre when the control room is far from the screen.
  • Receiving card: one or several per cabinet, depending on its resolution, receive that signal and turn it into the instruction that lights each pixel.
  • LED modules: the diodes light up with the colour, brightness and exact instant set by the receiving card.

The sending card and the receiving card always work in pairs, usually from the same manufacturer: the former lives in the control room or the video rack, the latter inside each cabinet of the screen.

Sending card and receiving card: not the same thing

It's common to confuse the two terms because "card" appears in both names, but they perform opposite functions. The sending card is at the source: it processes the video, sets the output resolution and splits it into the segments that correspond to each zone of the screen. The receiving card is at the destination, inside each cabinet: it receives the segment that belongs to it and turns it into the signal that lights the modules. A single sending card can feed dozens of receiving cards at once; without the matching receiving card inside the cabinet, that processed video would never become an image.

What defines an LED receiving card: resolution and refresh rate

The receiving card has a limit on the number of pixels it can handle. On very fine-pitch screens, with far more pixels per square metre, a single cabinet may need several receiving cards to cover its full resolution; on a wider-pitch cabinet, with less density, one is enough. It's one of the variables we weigh up when configuring demanding projects, such as control rooms or fine pitch P1.86 environments, where pixel density is at its highest.

The receiving card also sets the refresh rate: how many times per second it redraws the whole image. A high refresh rate prevents the flicker that TV cameras or phones do pick up even when the human eye doesn't notice it; that's why screens intended for recording or broadcast require a high frequency. Our high-brightness P3.91, for example, runs at a refresh rate of 1,920 Hz or more, and the Fine Pitch P1.86, designed for studios, at 3,840 Hz or more.

Colour and brightness calibration, pixel by pixel

Every receiving card also adjusts the brightness and colour balance of the modules it controls. LED diodes don't leave the factory perfectly identical to one another, so before the screen is delivered every pixel is calibrated so that no patches or tone differences show between adjoining cabinets. That calibration is stored in the receiving card itself, which applies it in real time while the screen is switched on, and it's what lets an LED wall made up of dozens of cabinets read as a single, uniform image.

Redundancy (loop): so a single fault doesn't take down the whole screen

Receiving cards on the same processor are usually connected in a chain, cabinet to cabinet, forming a loop. If a cable disconnects or a receiving card stops working, the system can reroute the signal from the other end of the loop, so that section keeps receiving an image instead of going black. It's the difference between losing a single cabinet —which is repaired or replaced at leisure— and losing the whole screen in the middle of an event. In live-event rental projects, that redundancy is what stops a one-off fault from ruining the day.

An industry-standard component

The receiving card isn't a proprietary part belonging to a single screen manufacturer: it's a standardised component built into most brands in the industry, with NovaStar, Colorlight and Linsn among the most widespread names on the market. That standardisation is an advantage for the end client: spare parts are compatible across different projects, and any technician familiar with the standard can diagnose a fault without depending on a single supplier. At LEDLEMON we fit receiving cards from these leading manufacturers depending on the project; our high-brightness P3.91, for instance, carries a NovaStar receiving card.

Tell us about your project

If you're considering an LED screen, the receiving card isn't something you need to choose yourself: it's a technical decision we make based on the resolution, refresh rate and reliability your project needs. Tell us where the screen will go, from what distance the audience will see it, and whether you need the kind of redundancy a live event calls for or a fixed installation. Request your quote with no obligation and we'll propose the right configuration.