The system is a Honeywell (Ultrak) HMXAT200 Switcher, HEGS3500 Keyboard, and 32 Honeywell KD6 PTZ cameras. The system was working properly. Recently, all PTZ cameras will continue to move slowly after they're panned. If you're panning a camera with the joystick to the right and release the joystick to stop, the camera will continue to pan slowly to the right. A slight bump to the left will generally stop the drift. I'm using the MaxPro protocol. I thought I might replace the RS485 board in the HMXAT200. Any other suggestions?