A cell phone is any portable telephone which uses cellular network technology to make and receive calls. The name comes from the cell-like structure of these networks. There is some confusion about cell phones being a different thing to smartphones, but technically, every mobile phone, from the latest Android handset to the simplest feature phone, is a cell phone. It is all about the technology used to transmit your calls, rather than what the handset itself can or cannot do. As long as a phone can transmit a signal to a cellular network, it is a cell phone.
The term Cell Phone is interchangeable with the terms Cellular Phone and Mobile Phone. They all mean the same thing. The term Smartphone has come to mean a cell phone which offers more advanced features than just calls, SMS messages and basic organizer software. Often, when talking about mobile phones, cell phone is used to describe a simple feature phone, whilst smartphone is used to describe more advanced touch screen phones.
The first commercially available cell phone was developed by Motorola between 1973 and 1983, and went on sale in the U.S. early in 1984. This huge 28 ounce (790 gram) cell phone, called the DynaTAC 8000x, cost $3995.00 and needed to be charged after just thirty minutes of use. The DynaTAC 8000x is almost unrecognizable as a cell phone when compared to the devices we use today. It is estimated that there were over 5 Billion cell phones in use at the end of 2012.
A cellular network, which gives cell phones their name, is made up of cellular masts or towers distributed across the country in a grid-like pattern. Each mast covers a relatively small region of the grid, usually around ten square miles, called a Cell. Large mobile phone carriers (AT&T, Sprint, Verizon, Vodafone, T-Mobile, etc.,) erect and use their own cellular masts and therefore have control over the level of cellular coverage they can provide. Several such masts can be located on the same tower.
When you make a call on a cell phone, the signal travels through the air to the nearest mast or tower, and is then relayed to a switching network and finally on to the handset of the person you are calling via the mast closest to them. If you are making a call whilst travelling, in a moving vehicle for example, you may quickly move from the range of one cell tower to the range of another. No two adjoining cells use the same frequency, so as to avoid interference, but the transition between cellular mast areas will normally be seamless.
In some countries, cellular coverage is almost total if you are with one of the large national carriers. In theory anyway. As you might expect, cellular coverage in built up areas is usually better than in more rural areas. Areas where there is little or no coverage are normally places where there is poor access, or areas where there is little benefit to the cell carriers (sparsely populated areas, for example). If you are thinking of changing your carrier, it is certainly worth checking to see what their coverage is like in your local area.
Cellular masts in built up areas such as cities are often quite close together, sometimes as little as a few hundred feet, because buildings and other structures can interfere with the signal. In open areas, the distance between masts can be several miles as there is less to disrupt the radio waves. If the cellular signal is just very weak (rather than non-existent), it is possible for consumers to buy a cellular repeater or network extender, both of which can amplify and boost a weak signal.