LED cards include LED receiving cards and LED sending cards. Synchronous LED display control card systems consist of sending cards, receiving cards, and DVI graphics cards. Asynchronous LED display control cards are mainly used to display various text, symbols, graphics or animations. Nowadays the mainstream LED control system manufacturers include Nova, Colorlight, Linsn, Zhonghang and so on. LED control card can be divided into: single and double color control card, full color LED control card, 3G 、4G wireless control card. LED cards are widely used in indoor and outdoor fixed LED displays, high-definition LED screens, stage rental LED screens, bar screens, etc.