12.2.1. Printed Material- Books, Magazines Etc

Printed materials are materials that contained hard copies (papers) of documents-data and information.. E.g books, newsprints etc.

12.2.2. Radio
Radio is an electronic device that transmits voice (audio) data or information over long distances using electromagnetic waves.

12.2.3. Telegraph

Telegraph is a device used for transferring voice (audio) data/information in over the air from one place to another. The signal or message sent by telegraph was called a telegram.          

12.2.4. Telephone

Telephone is an electronic device that can transmit voice or audio messages via wires or electrical waves. E.g. Land line, GSM handsets, smart phones etc.