Answer:
the signals have different frequency
Step-by-step explanation:
The way that interference is avoided in these cases is that the signals have different frequency. Cell phone signals travel in a very specific wavelength, how often this wave repeats in a given span is called the frequency. By having these signals in different frequencies it prevents the signals from mixing with each other and instead allowing them to reach their destination intact. Otherwise, the signals would combine into a mess of uncomprehensible data, which is what we call interference.