I am not yet in the digital age, but I have a normal hand held cell phone and it works fine in the bus.

We also have a hard wired digital cell phone converter that makes all our telephone jacks throughout the coach work with regular telphones. It allows us to locate regular phones throughout the coach, one of them a wireless, and it works as well as the little hand held cell phone. That hard wired device needs 120V AC power all the time, and it has a roof mounted antenna. Its service is through Verizon.