... protection PTZ CCTV keyboard controllerBasic Function:• Maximum cacade 16pcs sub-control keyboard• RS485 control bus,control 255 front end ... address and connect 128 devices in parallel simultaneously at the most• All input and output communication port ... code:0-254Communication ModeRS485 half-duplexCascade connection number16 sub-control at most,controller ID:0-15Joystickup,down,left,right, ...