Call phones

Cell phones work like this:



If a phone in cell A calls a phone in cell B, the call doesn’t pass directly between the phones, but from the first phone to mast A, then to mast B, and then to the second phone.

Cellphones that are moving between cells (when people are walking along or driving) are regularly sending signals to and from nearby masts so that, at any given time, the cellphone network always knows which mast is closest to which phone. If a car passenger is making a call and the car drives between cells C, D, and E, the phone call is automatically "handed off" (passed from cell to cell) so the call is not interrupted.