Don’t call yourself a master, just take out the display screen of your video intercom and use it as a small monitor. Keep the contrast switch board on the original display module, and there is a 4P socket on the other end. , generally the four digits of the power supply are positive\ground\ground\video. The power supply for black and white is 15-18V, and the power supply for color is 12V. You can connect the monitored video signal to the video and ground terminals, and you can watch it after powering on. Arrived.