Efreecity 7'' 700TVL 30x Zoom 8pcs IR Leds High Speed Dome Security Outdoor PTZ CCTV Camera Auto identification protocol , baud rate , eliminate the disadvantage of using dial switch traditionally Automatically identify 485 communication line straight polarity and reversed polarity and fix the major error in installation Night vision range reaches 120 meters Build in heater and cooling fan , speed dome constant temperature 5-20 degrees (standard configuration)