Your ROAM Transmitter comes from the factory with the maximum station number set to 15. This means that when you use the UP and DOWN buttons to change the station, you may change it to any number between 1 and 240. However, if you only have a 6-station controller, you will never need to access stations 7 through 9. Likewise, perhaps you will own a Hunter controller like the HCC which can have more than 9 stations. In this case, you would want to access the stations above 9.
Maximum station count per controller model: