Mobile phones

Mobile phones (telgam) or mobile (phone) or mobile (HP) or also referred to the electronic telecommunications devices that have the same basic capabilities with conventional phone lines fixed, but can be taken anywhere (portable, mobile) and unnecessaryconnected to the telephone network using a wired (wireless; wireless). Currently Indonesia has two systems of wireless telephone network, GSM (Global System for Mobile Telecommunications) system and CDMA (Code Division Multiple Access).The inventor of the first mobile phone system is Martin Cooper, a Motorola employee on April 3, 1973, although many so-called inventor of the mobile phone is a team from one division of Motorola (the division where Cooper worked) with the first model is the DynaTAC. The idea is triggered by Cooper is a communication tool that small and easily carried in a flexible traveling.Cooper and his team face the challenge of how to include all electronic materials into small-sized tools for the first time. But eventually a first mobile phone was successfully completed with a total weight of weighing two kilograms. To produce it, Motorola will cost the equivalent of U.S. $ 1 million. "In 1983, the portable mobile phone worth U.S. $ 4 thousand (Rp36 million), equivalent to U.S. $ 10 thousand (Rp90 million).Having succeeded in producing mobile phones, the next biggest challenge is to adapt the infrastructure to support mobile phone communication system by creating a network system that requires only 3 MHz spectrum, equivalent to five TV channels are channeled to the world.Another figure who is known to be instrumental in the world of mobile communications is Amos Joel Jr., who was born in Philadelphia, March 12, 1918, he was acclaimed as an expert in the field of switching. He got a bachelor's degree (1940) and master (1942) in electronic engineering from MIT. Shortly after the study, he began his career for 43 years (from July 1940-March 1983) at Bell Telephone Laboratories, where he received more than 70 U.S. patents in the field of telecommunications, particularly in the field of switching. Amos E Joel Jr., making a connector system (switching) from one region of the cell phone to another cell region. Switching this should work when mobile users move or move from one cell to another cell so that the conversation is not interrupted. Since the discovery of Amos Joel is the use of cell phones are becoming comfortable.sumper d.wikipedia.org