How telephones began 1
How Edison improved on the early telephone 4
How the sound of your voice travels 6
Sound waves into electric currents 7
The Transmitter 8
The Receiver 9
Telephone exchanges 12
Manual exchanges 14
Automatic exchanges 15
How the selectors work 17
Automanual switchboards 18
Dialling codes 20
Exchange systems 23
Long distance telephoning 24
Helping the electric currents over long distances 26
International services 29
Radio-telephones 30
The Post Office Tower 31
Telephoning by Satellite 32
Special services 34
Emergency services 35
Public services 37
Learning more about the telephone 38
Vocabulary 40