A method of changing the code of a radio communication system having a main unit and at least one remote unit is provided. The method generally includes in an embodiment the step of setting the code transmission frequency of the main unit of the radio communication system at a value within a frequency gap separating a first channel from a second channel of the main unit. The method also includes the step of setting the code transmission frequency of the remote unit at a value within a frequency gap separating a first channel from a second channel of that remote unit. The method further includes the step of selecting a code for encoding communication signals between the main and remote units and transmitting the selected code from one of the main and remote units to the other at the code transmission frequency.