A mobile phone, also known as a cell phone, is a mobile device used for voice and data communication over a network of base stations - sites where antennas and electronic communication equipment together create a cell in a mobile phone network. As we all know, today's mobile phones are used for many other purposes than the standard voice function, which is its primary purpose. Today, mobile phones are used for text messaging by means of SMS, for sending and receiving videos and photographs by means of MMS and for email and Internet services using GPRS. Mobile phones of modern times also support technologies like infrared and bluetooth, thus enabling inexpensive communication. For most of us, our mobile phone is one technological device we can't live without. We need it with us everywhere. How does this amazing piece of technology work? Let's find out. How Mobile Phones Work A mobile phone is a two-way radio, as it sends and receives radio signals to and from cell site base stations. When a person talks on a cellular phone, the voice message gets converted into radio waves. The radio waves travel through air until they reach a base station close by. The base station sends the call across the communication network after which the call reaches the intended receiver. A base station in the vicinity of the mobile phone being called sends radio waves for the receiver's device to detect them. The mobile phone of the receiver converts the signals into voice and the phone call is made. Base stations that form the telephone network for mobile phones are fitted with microwave antennas and are usually mounted on high structures such as a pole or a tower. They have low powered radio transmitters, which relay communication between the mobile phones and the switch. The switch connects the call to other subscribers of the same service provider. Mobile phones obtain power from batteries, which can be recharged from mains power. Nickel metal-hydride batteries or lithium ion batteries are used in mobile phones. Many have shifted to using lithium-polymer batteries as they are light in weight and offer flexibility in shape. Under the mobile phone battery lies a small microchip known as the Subscriber Identification Module, which is better known as a SIM card. This small chip stores the mobile phone's configuration details and information about the phone. When a mobile phone is turned on, it registers with the switch that then alerts the mobile phone of incoming calls. The mobile device listens to the signals being sent by surrounding base stations and switches smoothly between sites. A device can switch between networks without disturbing an ongoing call by transferring a call from one channel to another. This process is known as a handoff. Cellular technology has evolved through generations. The first generation mobile phones used analog networks and evolved in Japan in 1979. The second-generation systems began in Finland in 1991 and made use of digital technologies such as GSM and CDMA. The third generation systems began in Japan in 2001. They support high-speed data and voice services. 4G is a step ahead of 3G. Fourth-generation systems offer mobile Internet access, mobile TV, video conferencing and IP telephony and all these at remarkably higher speeds in comparison to earlier generation services. While you conveniently roam about carrying your mobile phone, the telecommunication network around you is at work, making and maintaining your calls and helping you stay 'connected'!