History of Cell Phones

This time I try to post the article about the phone, after earlier posting a lot of writing about computers. This article has been much in use as a training module on mobile phone technician, or on college campuses who majored in engineering elektro.Disini I just wanted to invite the reader to recall the history of mobile phones, because the phone when this is not a luxury item or items only in use by the upper middle class, over the times when this mobile phone have become used by all layers masyarakat.sesuatu odd thing when we are mobile phone users, but do not know sejarahnya.Insya God for the future I'll post more in depth about the phone, on reparations mobile phone, at least we can repair minor damage to the phone itself
Phone is a combination of technology is mated to Radio Telephone Communication Technology. The phone was first discovered and invented by Alexander Graham Bell in 1876. while the wireless communication (wireless) discovered by Nikolai Tesla in 1880 and was introduced by Guglielmo Marconi.

The roots of the development of digital wireless and cellular technology began in 1940 when the car phone is commercially introduced. When compared with the present development is so rapid, in fact the technology is experiencing bottlenecks in development for about 60 years. This is because the development of low-cost technologies such as transistors or semi-conductors have not been well developed. Once in temukannya transistors it is possible to be more rapid technological development.
Development of Cellular Technology
With the development of wireless technologies emerging today is a cordless phone technology (wireless) such as AMPS (Advanced Mobile Phone System), GSM (Global System for Mobile System) and CDMA (Code Division Multiple Access).
AMPS (Advanced Mobile Phone System)
AMPS is the first generation in mobile technology. This system is spent on the 800 Mhz band. This network mengguatkan very large integrated circuits consisting of Dedicated Computer and System Switch.

AMPS uses a frequency range between 824 MHz - 894 MHz is allocated on an analog phone. AMPS only be operated at 800 MHz band and does not offer other features that are commonly used in cellular services such as e-mail and browsing the web. The sound quality is not good as well as some technical issues to the constraints of the AMPS system is that the system is not developed and left behind even after evolving digital technologies.
GSM (Global System for Mobile telekomunication)
GSM is a second generation after the AMPS, GSM was first issued in 1991 and began developing in 1993 with the adoption by some countries like South Africa, Australia, Middle East, and North America. The rapid development of GSM caused by the use of a digital system that allows developers to exploit the use of algorithms and digital as well as enable the use of Very Large Scale Intergration (VLSI). To reduce and minimize the cost of the terminal Handled, by this time have used GSM Intelligent Network features (network intelligence).
GSM is a mobile telecommunication system using a digital cellular system. GSM was first made is prepared to be a mobile telecommunications system that has international coverage Multyplexing technology based on Time Division Multiple Access (TDMA). GSM has a frequency of 900 Mhz but it also uses the GSM 1800 MHz frequency with the name of the Personal Communications Network. GSM also provides services to transmit data at high speed using technology High Speed Circuit Switch Data (HSCSD) which is capable of transmitting data at up to 64 Kbps to 100 Kbps. In GSM networks in occupied Indonesia by PT. Telkomsel, Exelkomindo, Satelindo, Indosat.

CDMA (Code Devision Multiple Access)
CDMA is a third generation (3G). cordless telephone technology is perceived progress, with the emergence of various types of cellular phones. This is now emerging is a cordless phone that uses the Code Devision Multiple Access using spread spectrum techniques. Unlike the methods of the Global System for Mobile Communication (GSM) which uses Time Division Multiplexing (TDM), CDMA does not provide a marker at a frequency specific to each user. Each channel uses the full available spectrum. Individual conversations will be encoded or encrypted with a pseudo-random digital setting. CDMA is a development of the AMPS was first used by the U.S. military as a communication.

Basic Concepts of Cellular Technology
Cellular system is a sophisticated system because this system divides a region in a few small cells. It is used to ensure that the frequency can be extended to reach to all parts on a particular area so that multiple users can use their phones simultaneously without pause and without falter.

Definition of Mobile Phones
In cellular systems, to describe the geographic coverage area of the hexagonal representation is used. This area is called a cell (Cell). Why is hexagonal rather than circular shape to describe a cell?