Keyboard controller is a auxiliary product to the terminal receiver of variable speed intelligent dome, decoder and so on. Adopt EIA/RS-485 electronic port between the control keyboard and receiver. One keyboard controller can maximumly control 256 speed domes or decoders without adding the number of bus drivers and the maximum communication distance is up to 1.2Km. It is convenient to control and set the variable speed cameras via control keyboard. Also the control keyboard can directly control terminal decoder and achieve the control to front-end devices, such as camera, PTZ, len, light, windscreen wiper and so on.