History of The technology behind the cell phone emerged in different parts of the world at various points in the 20th century. The first known mention of the concept of a wireless phone can be traced back to internal memos was at AT&T in 1915. However, the idea was discarded at that time due to concerns by AT&T that it would compete with their burgeoning wired phone business. The idea of a network of antennas relaying broadcast signals over great distances would emerge at Bell Labs in 1947. Due to the various technologies needed to produce a cell phone, the first true cell phones and cell phone networks would not come into existence until 1978. Evolution The earliest form of wireless vocal communication was that of two-way radio that first appeared in Europe in the 1920s. During World War II, two-way radio communication was given military uses. Around this time, Motorola's developed a portable two-way radio for use by the United States military. Shortly after, two-way radio technology would find its way into use in emergency and civilian transport vehicles. In 1965 Ericsson created the first working automobile-based telephone, but it had many limitations. The final technology needed to produce the cell phone came about with the emergence of the first cellular antenna networks in 1971. In 1978 Bell Labs began offering a limited cellular phone service in the United States and in 1979 NTT began offering full cellular service in Japan. By the early 1980s, companies offering full cellular phone service were popping up in virtually every corner of the globe. Type The four most common types of cell phone are the traditional handheld phone, the flip phone, the touchscreen phone and the slide phone. The traditional handheld phone is one with an open-face viewing screen and touch pad resembling a typical house phone. The flip phone features a cover over the touch pad that can be flipped up to access the touch pad and viewing screen. The touchscreen phone has a touch-sensitive viewing screen that can be used to access the various features of the phone. The slide phone features a part of the phone that either slides or flips to reveal a full keyboard underneath for use in messaging or computing. Features The number of features available with cell phones is virtually unlimited. Common features include a wireless ear piece for hands-free talking, usage as a modem, text messaging, PDA handheld computer, MP3 music player, camera, voice recorder, internet access, customized ringtones, calendar and GPS. Significance The subtle impact these tiny devices have had on modern civilization in just a few short years is truly revolutionary. Communication with anyone anywhere is now nearly instantaneous. News and information, of every conceivable form, can now be acquired at the touch of a button. Videos, music, games and other forms of entertainment are easily accessible. In short, the cell phone has quickly become an absolute necessity for a growing percentage of the world's population.