Focus on checking the connection of the four antennas of the host. The original antenna of the equipment must be used. The antenna should be placed higher than 1.8 meters. There should be no obstructions within 0.5 meters around the antenna. The spacing between the antennas should be more than 5 cm. The spacing between the antenna and the wireless unit should be less than 60 meters and there should be no obstructions in the middle. The D antenna is responsible for receiving and sending the switch control signals of the wireless unit. The signal frequency is about 450 MHz, Pay attention to whether this frequency band is interfered by external equipment, and ensure that the wireless signal environment is clean before normal use.