We must pay attention to 7 points when using LED display wall  control card to ensure the safety of ourselves and equipment.
1. It is strictly forbidden to plug and plug the serial port with hot line, so as to avoid damaging the computer serial port and control card serial port due to improper operation.
2. It is strictly forbidden to adjust the input voltage of the control card when the system is live, so as to avoid damaging the computer serial port and control card serial port due to improper adjustment and high voltage. The normal working voltage of the control card is 5V. When adjusting the power supply voltage, you should remove the control card and adjust it slowly with a multimeter.
3. It is strictly forbidden to short circuit the ground terminal of the control card with the display frame, otherwise, once static electricity accumulates on the display frame, the computer serial port and the control card serial port will be easily damaged, resulting in unstable communication. In case of serious static electricity, the control card and the display unit on the screen will be burned out. Therefore, when the outdoor screen or communication distance is far, users are advised to use serial port isolator to avoid damage to computer serial port and control card serial port due to ground circuit, surge, induced lightning stroke, hot swap and other harsh environment.
4. It is necessary to ensure the correct connection between the control card and the computer serial port, so as to avoid damaging the serial port of the control card and the computer due to the incorrect input signal.
5. Do not connect the control card to the unit board. It should be led directly to the switching power supply as far as possible. The voltage of the unit board is unstable during the working process. It will cause the control card to be fast and sometimes slow, seriously unable to communicate or program running, which needs to be repaired. Especially, the U disk control card may not be able to read the disk or read the disk error in the case of voltage instability.
6. Indoor, 16 scan unit board must not be connected to the whole screen debugging. Many indoor monochrome or dual color, or even full-color, are directly connected to the control card for power on without debugging, which may burn the 4953 chip behind the unit board in a large area. Please connect only one unit board for debugging. After debugging, unplug the power supply, and then connect the control card.
7. Please keep the control card working in a dry and relatively stable environment. High temperature, humidity and dusty environment are extremely unfavorable to the control card.