Frequency hopping sytems

 These days the main brands like Spektrum, Futaba and JR tend to use these frequency hoping systems but it is worth checking. The Spektrums system is DSMX, the Futaba is FHSS and the JR system is DMSS.
If you are buying a rtf plane with the radio included then chances are it will be one of the older style systems but don't worry they work perfectly well and for a number of years even the aforementioned big names thought it was ok.