ABSTRACT
Telephony is the transmission of sounds, particularly spoken words, over distances. Wireless telegraphy or telephony is transmission not by means of wire or cable but through the atmosphere.
The final distinction we need to be aware of is between point-topoint transmissions, which take place between a sender and a single receiver, such as those which normally occur on the telephone, and broadcast transmissions, which take place between a sender and an indefinite number of receivers. Broadcast transmissions are usually offered to anyone who has the equipment to catch them.
