You post reminded me of an earlier thread I still had open in my browser. I see you're already aware of it.I know the other thread has links to some documentation on these sorts of protocols, but it would probably be a good idea to add links here to the devices you want to use.I'd think you'd want to use an Arduino with multiple UARTs such as a Mega. RS485 driver ships are pretty easy to come by. Converting RS485 to/from RS232 shouldn't be hard. It's just a matter of having the right chips.What sort of input device were you thinking of?I recently worked on some joystick/servo code and I used this joystick to control a little pan/tilt gizmo.The code I used (and a links to a couple videos showing the code in action) can be found here.Other control options were discussed in this thread.I'm not sure what sort of option you have I think it's really nice to be able to use the joystick to control either the position of the camera or the speed of the camera.Do you have an Arduino in mind for this project? As I mentioned earlier, I think you want an Arduino with multiple serial ports.