An example of a telephone is a network or system that transmits electrical signals so you can call someone in Japan from your home in New york.
An example of a telephone is what you use to take advantage of a system of lines through which electrical signals are transferred.
Telephoned the police station.
She telephoned to invite us to the party.
An example of telephone is when you use a cell phone to call your friend and say hi.
I telephoned that I was sick and could not come to work.