In my proper, elaborate theory of planes of reality, the frequencies pertain to particle interaction. Specifically, particles of a given band width interact only with other particles of that band width, and never of other band widths. There is the question then as to why particles don't simply alter their band widths and begine to belong to another plane of reality. For this, we can suggest a way of doing it in such a way that 'inter dimensional circuit' must be completed first.
Usualy, existent throughout space, there is that which prevent particles from shifting to other frequencies. Thus 'space' is like a sea. Wherever there is a 'hole' in this sea, particles can shift their bandwidths. Thus for a given band width, altering the particle density at the vicinity of the 'hole'. Two such 'holes' will be an 'entry' and 'exit' points of the circuit.