Option # 4 sets the throttle ID of your throttle.
Each throttle in your LocoNet system can have its own unique ID to support advanced LocoNet functionality. Products that use this feature will usually require each throttle in your system to have a unique ID.
We recommend changing this ID only when specifically directed to do so by the manufacturer of a LocoNet compatible product that requires unique throttle IDs for operation. You may use any ID in the range of values x00-x7F (hex) and you must be sure that every throttle in your system has a unique ID #.