Mobile phone

From Simple English Wikipedia, the free encyclopedia

A modern mobile phone
A modern mobile phone

A mobile phone or cellular phone is a little portable radio telephone.

Some of the world's largest mobile phone builders are Alcatel, Siemens, Fujitsu, LG, Motorola, NEC, Nokia, Panasonic, Philips, Samsung, Sanyo, Sharp, Sony Ericsson, and Toshiba.

The mobile phone can be taken to long distances and used to communicate. Each cell phone is linked to a base station. The cell phone has more functions, it is used for:

  • talking to others;
  • sending and receiving e-mails, text and multimedia messages;
  • registering contacts;
  • using calculator, currency, alarm, etc. functions;
  • enter Internet;
  • playing games.

Contents

[edit] History

The idea of cell phones appeared in 1947. The idea was developed in 1968 by two companies - AT&T and Bell Labs - which invented a new cellular system.

Later, in 1973, Dr. Martin Cooper (the real inventor of the first portable cell phone) made the first cell phone call. Cooper ( general manager of Systems Division, Motorola) called his rival Joel Engel from Bell Labs.

Beginning with 1981 to 1983 in USA were created two cellular system (Washington-Baltimore and Chicago).

[edit] Technology

A cell phone has combined two technologies: telephone (invented by Alexander Graham Bell in 1876) and radio (invention of Nikola Tesla in the 1880s).

Cell phones work as two-way radios. They send electromagnetic microwaves from base station to base station. The waves are sent through antennas. This is called wireless communication.

There are two types of cell telephone networks:

  • analog networks
  • digital networks

Most of the older cell phones use analog networks. The modern phones use digital networks.

Digital networks are also known as Second Generation technologies. They differ either by technology or by speed. The most used digital network is GSM (Global System for Mobile communication). It is spread mainly in Europe and North America. Then there is CDMA (Code-Division Multiple Access) network and TDMA (Time Division Multiple Access). Both are used in USA, South Korea, etc.

Cell phones work by using radio frequency bands to send the waves. The frequency is measured in Hz. Low frequencies offer good connection. Higher frequencies can sent the signal further. For GSM, are usually used four main frequencies around the world: 850, 900, 1800 and 1900 MHz. Europe uses 900 and 1800 Mhz and North America uses 850 and 1900 Mhz.

Today there are cell phones that work on two, three or four frequencies. The most advanced phones work on all channels. They are called 'world' phones and can be used everywhere. CDMA phones use the same frequencies as GSM.

Beginning with 2007, new technologies such as EVDO (Evolution Data Optimized) and UMTS (Universal Mobile Communication System) are used. Today they are tested in Europe. It is planned that all smartphones (modern phones) use these technologies.

[edit] Viruses

Cell phone viruses are electronic program that attacks cell phones and PDA (personal digital assistants) devices. They differ from computer viruses (are not so dangerous) and are not widely spread. They usually attack the software (the program that make the phone work).

There are electronic attacks called malwares, which are not actually viruses but are harmful to the cell phone.

Cell phone viruses attack only smartphones (latest models of phones), which have Symbian, palmOne and Windows Mobile operational systems. This mean that today only 4 % of the cell phones can be attacked. Older cell phones with simple programs are not threatened.

Most of the viruses a written as proof-of-concept programs, which finally work as viruses. The Group 29.a. is an international group of virus writers. They specialize in creating viruses.

If the cell phone is infected then all information on it is lost. Some dangerous viruses can even modify the operating system of the cell phone.

To be able to use the cell phone again, it should be formated to factory settings. For this, many cell phones have a special code. An infected phone can also be saved by anti-virus software.

There are several anti-virus companies (Trend Micro, F-Secure, Symantec) which work on a cell phone anti-virus. In Japan there already are phones with built-in anti-virus software (company NTT DoCoMo) made by McAfee Inc.

[edit] Distribution of viruses

There are three main ways a cell phone can be infected:

  • 1.MMS or SMS messages.
  • 2.Internet inappropriate programs (only after their downloading and installing).
  • 3.Bluetooth. To protect your cell phone, set Bluetooth to the 'hidden' mode.

The viruses are usually hidden inside some other programs or messages. They are started only after downloading and installing the program or messages.

[edit] Types of Viruses

Timifonica. This virus was known in 2000. It was a virus that sent text messages from infected PCs to phones.

Trojan. It is considered the first virus sent from cell phone to cell phone. It was known in August 2004. The Trojan was created as an anti-piracy program the game Mosquito against illegal distribution. The virus sends itself through SMS text messages.

Cabir. This virus was known in July 2004. It was a creation of group 29a. This virus is spread through Bluetooth to accessible phones. It is spread as an SIS file (Symbian OS distribution file). Cabir attacks phones with Symbian OS. When the phone is infected it displays the message 'Caribe'.

Commwarrior. This virus appeared in March 2005. It infects phones with Symbian OS. The Commwarrior worm spreads itself through Multimedia Messaging System (MMS) following the address book list.

Comwar. This virus worm is spread through MMS messages and Bluetooth. It also attacks phones of Symbian Series 60 OS.

Duts. This virus is the first to infect cell phones and Pocket PCs. The Duts attacks the .exe files and files that are bigger than 4096 bytes.

Skulls. If a cell phone is infected with this virus, then the desktop icons are replaced with images of skulls. The Skull makes all phone applications useless.

Lasco.A. This virus spreads through Bluetooth and also can be attached to files. The Lasco.A is a result of mistakes in cell phone program. It is also present in PCs.

[edit] External links

Look up Africa to receive help from mobile phones in Wikinews, the free content news source