Communications

Introduction

Communications between people were in written or oral and transmitted via the transportation available at the time until 1835, when telegraphy was invented.   From that time, information exchange between people could be made without transportation, thus making it immeasurably faster and cheaper, which increased the productivity of all industries and, consequently, American living standards.   Later inventions in telephony and computer networks increased communications still more.   Radio and television are not only entertainment media.   They supply information regarding safety and health and therefore contribute directly to living standards.   Radar and sonar contribute to ship and plane safety by communicating location and position.   Sonar also is used in medical diagnostics.