Mobile radio and mobile telephones

Mobile radio and mobile telephones
Two-way mobile radio communication was first used around the time of World War I. Mobile radio is still used today across the globe by taxicab companies, police departments, fire departments, trucking companies, and marine operations. Mobile radio users only communicate with each other; they cannot connect to the public-switched telephone network. Users take turns speaking because the system only allows for one-way communication. But the price of wireless telephone service is dropping and, in most cases, it is now cost effective for a company to replace its mobile radios with cellular phones.

Mobile telephones were developed because people wanted to call from their cars to normal landline phones. The first mobile phones were very expensive, and each city could only handle a small number of simultaneous phone calls. One of the first mobile phone systems, in St. Louis, could not even accommodate 100 simultaneous calls. Mobile telephones were given their own frequency band by the FCC, and this small portion of the airwaves would only accommodate a small number of users. Cellular telephone service changed all of this.