A mobile phone is a wireless telecommunications device. Basically, radio frequencies are responsible for linking mobile radio transmitters (or just transmitters) to transmitting and receiving base stations. Standard telephone networks are connected to users by receiving 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 the mobile phones.
To avoid radio interference, each cell uses different frequencies than those used by surrounding cells. However, cells that are far enough apart from each other can use the same frequencies. When a mobile phone leaves one cell and enters another, the phone 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 main parts of a mobile phone:
o LCD Display – o Liquid Crystal Display is the front display with little electrical power. It is usually thin, so it is a good fit for battery-powered cell phones.
o Menu Button: This is the control key that activates the menu. The menu page accesses various phone features such as settings, reminders, games, messages, and media player.
o Keyboard: is a group of alphanumeric keys on a keyboard. Keys are pressed to enter data, such as when composing a message or entering the number to be called.
o Antenna – emits and collects radio signals. Some older cell phone variations have antennas attached to the outside of the phone. The antennas on later models are built in-house.
o Battery: a device that stores energy and is useful in electrical form. The first mobile phone batteries were made of nickel cadmium (NiCad). This element is believed to be harmful to the environment and should be disposed of as toxic waste. It also causes interruptions in sending information when the battery is not properly charged. It has a tendency to lose its power quickly if not used properly and regularly. Nickel cadmium tends to go bad when overcharged.
Nickel metal hydride (NiMH) was used in successive battery productions to solve the problems that NiCad brought. They are toxin-free and relatively safe for the environment. It is not necessary to empty them completely before recharging them. However, overcharging can also affect battery life.
Currently, most rechargeable batteries are made of lithium ion. They last longer than NiMH and can be overcharged without damaging the phone unit.
o Microphone: a device that picks up and receives sound energy. You can amplify sounds.
o Headset – This is also known as a headset, because hands-free kits or sets. A headset allows users to talk to someone without having to hold the unit close to their ears. This is very handy for people who are driving.
o Power switch – It is the button to turn the mobile phone on and off. A faulty power switch will not be able to power on a drive. Always check your terminal leader if it is connected with the power IC.
o Battery Terminal – Connects the battery to the mobile phone. These are usually the little shiny gold metals that we see before we put the batteries in.
o Power IC: acts as a voltage regulator and ignition. The entire unit will not work if it is faulty.
o Oscillator – also called clock frequency. It creates low frequencies, which are used to run digital components and help postpone power in the event of a failure.
o Frequency Divider – Used in mobile phones to divide the clock frequency to achieve an accurate frequency for running digital components. This part is Integrated Radio ICs, the equivalent of Hagar IC or Mojoelner in Nokia mobile phones.
o CPU: The central processing unit is the brain of the mobile phone and controls the main parts of the unit. It is vital in the boot test process. The CPU is vitally associated with memory chips and flash chips.
o Flash Chips: Flash chips contain boot information. It has stored instructions for the CPU to control other components.