A mobile phone is a cordless telecommunication device. Basically, radio frequencies are responsible for linking mobile radio transmitters (or simply transmitters) to transmission and recipient base stations. Standard telephone networks are hooked up to users by the recipient stations. The geographic region offered by a cellular system is subdivided into areas called cells. Each cell has a central base station and two sets of designated transmission frequencies. One set is used by the base station and the other by mobile telephones.
To avoid radio intervention, each cell uses frequencies different from those used by its surrounding cells. However, cells that are sufficiently distant from each other can use the same frequencies. When a mobile telephone leaves one cell and enters another, the telephone call is transferred from one base station to another, and the set of transmission frequencies to the next, using a computerized switching system.
The process of transmitting radio frequencies from one cell phone to another can be made possible through the different parts and functions of the mobile phone.
These are the major parts of a mobile phone:
o LCD Screen – or Liquid Crystal Display is the screen in front with little electric powers. It is typically slim making it well fitting for battery powered cellular phones.
o Menu Button – this is the control key that activates the menu. The menu page has access to various phone functions like setting, reminders, games, messages, and media player.
o Keypad – is a cluster of alphanumeric keys in one pad. The keys are pressed to input data, like when composing a message, or inputting the number to be called.
o Antenna – it emits and picks up radio signals. Some earlier variations of cellular phones have antennas attached outside the handset. Antennas in later models are built internally.
o Battery – A device that stores energy and is handy in electric form. The earliest mobile phone batteries were made of Nickel Cadmium (NiCad). This element is believed to be environmentally harmful and needs to be disposed as toxic waste. It also causes interruptions in sending information when the battery is not charged properly. It has a tendency to lose its power quickly if not utilized properly and regularly. Nickel Cadmium tends to blight when overcharged.
Nickel Metal Hydride (NiMH) was used in the succeeding productions of batteries to resolve the problems that NiCad brought. They have no toxins and are relatively safe for the environment. They don’t need to be completely drained prior to recharging. However overcharging can affect the life of the battery too.
At present, most rechargeable batteries are made from Lithium ion. They last longer than NiMH, and can be overcharged without causing harm to the phone unit.
o Microphone – A device that picks up and receives sound energy. It can amplify sounds.
o Earpiece – This is also known as earphones, car kits or hands-free sets. An earpiece lets users talk to someone without holding the unit to their ears. This is very practical for people who are driving.
o Power switch – It is the button for turning on and off the mobile phone. A faulty power switch will not be able to turn on a unit. Always check its terminal leader if it is connected with the power IC.
o Battery terminal – It connects the battery to the mobile phone. These are usually the small shiny gold metals we see before placing the batteries.
o Power IC – This acts as a voltage regulator and power on. The whole unit will not work if this is faulty.
o Oscillator – also called clock frequency. It creates low frequencies, used to run digital components and helps to put off power on failure.
o Frequency divider – used in mobile phones to divide clock frequency and achieve accurate frequency to run digital components. This part is integrated radio ICs, the equivalent of Hagar IC or Mojoelner in Nokia mobile phones.
o CPU – Central Processing Unit is the brain of the mobile phone and controls the major parts of unit. It is vital in the boot testing process. CPU is vitally associated with memory chips and flash chips.
o Flash chips – Flash chips hold booting information. It has stored instructions for the CPU to control other components.