Cell phones have a weak electromagnetic field in the frequency range of Microwave. Land Telephone line use means, which confine your movement somewhat, as you have to be connected to the system on the ground or in a location, which has phone lines. Even the walk-around phones in the house have limited range.

Satellite communication systems are often expensive to use and you generally need a clear shot of the satellite. Since we know that the brain runs on frequencies and the these frequencies are in the ELF range, if we can match the two people