What are at least 3 inventions that led up to the invention of the cell phone?

Answer 1

Some inventions are the 'car telephone' fitted in a centre console of a car and operated as a fixed item powered from the car's battery and operated as a radio telephone [like police car telephones]; next were smaller portable versions that had its own battery around 1984-5 in England and were the size of shoebox, then the handheld items with rechargeable battery cells and analog signalling. All these depended on the invention of wireless networking that were operated by software on lowcost processors and mainframe computers to provide the system for all the calls other services and the billing and invoicing data collection. Digital systems use packets of data containing digitalised voice input and output on the phones.