ABOUT CELL PHONE TECHNOLOGY AND INTERNET ACCESS THROUGH THE CELLPHONE

The basic function of the cell phone is to transmit voice and other information through the cellular network. This network however has the ability to transmit any kind of information, but with less capacity and more expensively than ordinary data networks.

All cell phones have the ability to transmit and present voice and messages through that network. The capacity in the network can however be used also for internet transphere, and some cell phones also have capacity to access other networks or techical units outside the cell phone network.


Things to concider beor chosing a cellphone plan

Things to concider when one is searching for the best cell phone and plan for you are: Do you call mostly locally or often long distance or abroad? Will you often use internet through the cell phone. Will you need to load things between your cell phone and your computer? Will you play music on your phone? Will you often need GPS positioning? Is coverage at all places important? How often do you call, and how long do you call each time? Will you often write and calulate complicated things on your phone? Will you use your phone for chat often?


Internet through the cell phone network

Many cell phones can access the internet through the cell phone network. These are commonly called WAP-phones. Nowadays most cell phones have this capability to some extend.These phones use a service called "wirelesss internety service through" in the cell phone network.  There are several variants of this service with various speeds. GPRS is usually the slowest, while 1xRTT and EDGE are faster.


Accessing internet through wireless local networks

A cell phone can also have installed the capability to access a local ADSL internet connection through wireless connection. Such phones are calle Wi-Fi phones. This capability can however only be used in buildings or areas that have a ADSL connection and where this connection have a wireless transmitter. By using this capability, one get access to a much greater speed, and there is no extra costs using the network.


Accessing the internet from your PC using cell phone as a modem

Some cell phones can be used as such a modem between a PC and the internet provider, so that the information from the internet is displayed on the PC. In this case the cell-phone resceives the data theough the cell phone network and wires it over to the computer. In orther to be used this way, the cell-phone must have a data-port and hardware/software that let it separate out the internet traffic that is going to and from the PC. This functionality is usually just called modem.


Enabeling your PC to access data from the cellphone network without a cellphone

You can get cards for your PC, modem cards, that let your PC access data through the cell phone network. Then you do not need any cellphone to use the cell phone network as an internet data channel.


Wireless enabled web-sites

Basically a wap enabled phone can access any site. But if the pages of the site is too large, too complicated or contain heavy pictures, the phone will not be able to display the content with a useful speed an in such away that it can be viewed usefully. Website owners must therefore make their sites wireless friendly. That implies dividing the content in several smaller pages than fewer larger, and having a simple page layout. Some content providers have the strategy of making their basic sites wireless friendly, while others make separate wireless-friendly sites.


Display capabilities in the cell phone

There are differences among phones about the ways information from the internet can be displayed on the phone. The display capabilities depend both of the speed of the internet service used and about the display functions in telephone itself.

Some phones can only display simple texts from the internet. Others can display graphical immages. Stll others have the speed and functions to display video animations an TV sendings through the net.


Web-browsers for mobile phones

It is not possible on a practical way to show a whole complicated web-page on a mobil phone. Therefore mobile phones ned web-browsers that can divide each page up in practical parts to be  displayed at a time and that can allow the user to switch easily between the parts of the page. A mobile phone also have limited memory, so that to many pages or even a  whole complicated page canot be cashed simultanously.

Browsers that display web-pages in a manner practical for a mobile phone and that fetches and cashes web-content in a practical way have been developed, for example opera mini.


Wireless connection between the cell phone and PCs - Bluetooth

Most cell phones have the capacity to trasnmit data to and from a PC or other data equipment through a cable. In som ecell phones this transmission can be effected wirelessly. This wireless transmission confirms usually to a standard called Bluetooth. Phones that can connect to a PC wirelessly are usually called Bloetooth phones. To do so, also the PC must have bluetooth capabilioties.


GPS or global positioning service on the phone

The GPS network based on satellites in orbits around the globe can be used to determine where you are at any time. Some cell phones have in-built GPS capacity. Suchs phones can be used to determine the exact geographical position you are on at any time.Advanced GPS phones also have inbuilt map services, so that you can see on a detailled map where you are.

ABOUT ELECTRONICS AND ELECTRONIC DEVICES

Electronics is the study of the flow of charge through various materials and devices such as, semiconductors, resistors, inductors, capacitors, nano-structures, and vacuum tubes. All applications of electronics involve the transmission of power and possibly information.

When information is transmitted, it is coded by the strength of the voltage or current in the circuit.

Although considered to be a theoretical branch of physics, the design and construction of electronic circuits to solve practical problems is an essential technique in the fields of electronics engineering and computer engineering.

Devices, products and components using electric current or voltage are also generally called electronics.

The study of new semiconductor devices and surrounding technology is sometimes considered a branch of physics. This article focuses on engineering aspects of electronics. Other important topics include electronic waste and occupational health impacts of semiconductor manufacturing. Here are the main types of electronic ciruits explained.


Analog circuits

Hitachi J100 adjustable frequency drive chassis.Most analog electronic appliances, such as radio receivers, are constructed from combinations of a few types of basic circuits. Analog circuits use a continuous range of voltage as opposed to discrete levels as in digital circuits. The number of different analog circuits so far devised is huge, especially because a 'circuit' can be defined as anything from a single component, to systems containing thousands of components.

Analog circuits are sometimes called linear circuits although many non-linear effects are used in analog circuits such as mixers, modulators, etc. Good examples of analog circuits include vacuum tube and transistor amplifiers, operational amplifiers and oscillators.

Some analog circuitry these days may use digital or even microprocessor techniques to improve upon the basic performance of the circuit. This type of circuit is usually called 'mixed signal'.

Sometimes it may be difficult to differentiate between analog and digital circuits as they have elements of both linear and non-linear operation. An example is the comparator which takes in a continuous range of voltage but puts out only one of two levels as in a digital circuit. Similarly, an overdriven transistor amplifier can take on the characteristics of a controlled switch having essentially two levels of output.


Digital circuits

Digital circuits are electric circuits based on a number of step-wise voltage levels. Digital circuits are the most common physical representation of Boolean algebra and are the basis of all digital computers. To most engineers, the terms "digital circuit", "digital system" and "logic" are interchangeable in the context of digital circuits. In most cases the number of different states of a node is two, represented by two voltage levels labeled "Low" and "High". Often "Low" will be near zero volts and "High" will be at a higher level depending on the supply voltage in use.

Computers, electronic clocks, and programmable logic controllers used to control industrial processes (PLS), are constructed of digital circuits. Digital Signal Processors are another example.

Examples of digital circuits are: Microprocessors , Microcontrollers , Application-specific integrated circuit(ASIC) , Digital signal processor (DSP) , Field Programmable Gate Array (FPGA) , Mixed-signal circuits

Such higly complex ciruits are built up of smaller units like: Logic gates , Adders , Binary Multipliers , Flip-Flops , Counters , Registers , Multiplexers , Schmitt triggers , Highly integrated devices:


Mixed-signal integrated circuit

Mixed-signal circuits refers to integrated circuits (ICs) which have both analog circuits and digital circuits combined on a single semiconductor die or on the same circuit board. Mixed-signal circuits are becoming increasingly common. Mixed circuits are usually used to control an analog device using digital logic, for example the speed of a motor. Analog to digital converters and digital to analog converters are the primary examples. Other examples are transmission gates and buffers.

(This information is mostly fetched from wikipedia.org and it is therefore free to reuse)