The sending Card is a typical component in Synchronous systems. This card is responsible for converting the input video signal (HDMI / DVI) to a format that the screen can interpret. In most cases, the outputs from these cards to the LED screen is via a conventional CAT6 / 7 network cable.
This type of Sending Card integrates a central FPGA controller from the Xilinx or Altera manufacturers, programmed with the VHDL programming languages. The FPGA (Field Programmable Gate Array) perform the conversion of the digital video data and divide it into millions of small parts so that they can be interpreted by the Receiving Cards that are installed on the LED screen.
Up till now, it has always been necessary to use sending cards in synchronous LED screens, since, as the screens are made of LEDs or individual pixels, it becomes necessary to use electronics and a specific communication system in order receive the data to perform their function. This is why it is necessary to use a “translator” element that carries out this job. Currently, with the power of computer equipment, some manufacturers do not use this card and use the computer itself to perform this task in real time, thus avoiding using an additional element to perform this conversion.
- FPGA. system of logic gates that describe the process that the electronic circuit has to follow, this is done by loading a bitstream in its internal memory.
- Gigabyte output ports. Exit ports to the screen. These ports are individual, being able to emit different images on two screens or reproduce the same contents separately.
- USB port. for charging and configuration of technical parameters on the LED screen. In some models we find several USB ports where each of them is used to synchronize several Sending cards.
- Jack Port. Stereo audio output.
- PCI Express slot. To connect in a PCI Express slot of a desktop computer.
- Power port. 5V power with multipin connector.
Sending cards are usually classified according to the resolution capacity they are capable of processing. We can have cards that can obtain maximum output resolutions of 1024 x 768 and higher ones with capacities of up to 4K.
It is necessary to adapt the resolution of our LED screen to the capacity of each Sending Card. In addition to the resolution capability they can offer, they can also perform other auxiliary functions:
– Brightness Sensor
These sensors are connected to the sending card, allowing to control the brightness of the LED screen according to the room lighting conditions. For example, we can program the screen to reduce its brightness during nighttime so as not to annoy a passerby. That is, these brightness sensors allow us to optimize the brightness of the screen considering the room’s lighting conditions.
– Temperature sensor
The temperature sensors measure the room temperature and send it to the card so that it can be displayed on the LED screen itself.
This option is configured from the LED screen’s software and you can customize at what time you want to display the environmental temperature captured by the sensor. It is important for the temperature sensor to be installed in an area where auxiliary temperatures do not interfere (shaded areas, near heat sources, etc.). Sometimes, instead of using the temperature sensors, it is necessary to collect the environmental data that is offered from specialized web pages and these are captured and displayed on the LED screen itself.
– Error detection on the LED screen
The more advanced and expensive models on the market allow you to carry out exhaustive analysis of the electronic performance of the LED screen. This allows you to have full control over the adequate operations of the LED screen. Due to the high price of these systems, it is usually only recommended for companies that have large fleets of advertising screens spread over very wide geographical areas.