The Automation Systems Can Control The "Hand Off" Of A Customer Handset Moving Between One Cell And Another So That A Call In Progress Continues Without Interruption, Changing Channels If Required.
In The Earliest Mobile Phone Systems By Contrast, All Control Was Done Manually; The Customer Would Search For An Unoccupied Channel And Speak To A Mobile Operator To Request Connection.
An input mechanism to allow the user to interact with the phone. These are a keypad for feature phones, and touch screens for most smartphones (typically with capacitive sensing).