GCSE ICT UNIT 2 ( Exchanging information )
Wifi : communication technology that makes use of radio waves in order to connect to a local area network.
Each wifi enabled device searches for a wifi base station nearby. Once it finds the network you need to type in the correct password to connect. Some networks aren’t password protected and your device will automatically connect. Access points = hotspots . The wifi base station usually is a network router / ADSL modem. The router is often connected directly to the internet on a standard ADSL telephone line .
The max speed of a wireless network using 802.11g standard is 54mb/s but in reality they are often slower. A hard-wired gigabit network that can transmit 1000mb/s . Speed is mostly influenced by the strength of the radio signal – the weaker it is the slower the speed.
Usually wifi network have a range of 32m.
Wifi has many uses including : maps , to complete homework , google questions , to send files , to talk to people , to print , to watch films/ videos and to listen to music .
Advantages of wifi :
* Convenience – allows users to access network resources from nearly any location .
* Mobility – users can access internet outside their normal work environment .
* Productivity – users connected to a wifi network can maintain access to their work when they move to place . For a business this is useful as an employee can be more productive as their work can be completed for nearly any location
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* Deployment – setting up access points is a lot easier than have to pay for actual cables and get them fitted .
* Cost - less expensive as you don’t have to pay for the cables and for them to be fitted.
Disadvantages of wifi
* Security - even though its encryption , the data can still be hacked into .
* Range – the range isn’t that large (32m) . Large businesses will need many wifi points , the costs can quickly add up
* Reliability – wifi signals are subject to a wide variety of interferences that are beyond the control of the network administrator .
* Speed – the speed of wifi (1-54mb/s) is slower than most common wired networks (100mb/s to several gbs)
* It can only connect to a limited number of devices as they all have to share a limited number of radio channels. So cables are better for a large business that uses computers frequently .
Hotspots are very useful for large business are the usual range of 32m isn’t large enough . These hotspots allow one network to be shared over a large distance.
3g is a mobile communications standard that allows mobile phones and other electronic devices to access the internet wirelessly .
4G is a mobile communications standard to replace 3g , it provides wireless internet access at a much higher speed.
Bluetooth is a short range wireless connection between devices that allows you to share files. It was developed so devices close to one another could exchange data. The range is around 10m.
Bluetooth is called Bluetooth because of the 10th Century second king of Denmark , King Harald Bluetooth who was famous for uniting Scandinavia just like how Bluetooth is supposed to unite pc and cellular industries with a short-range wireless link.
Bluetooth can be used to share videos, keep files in sync and music . A more common use is to pair the device with the Bluetooth system in the car , so you can accept calls through the car. This allows you to talk and keep your hands on the steering wheel .
Bluetooth sends radio waves which are sent between devices. A Bluetooth product eg Watch will contain a tiny computer chip with a Bluetooth radio and software.
* Excellent for short range communication
* Does not require cables
* World-wide standard so ALL Bluetooth certified devices are compatible
* Fully automatic , it can autosense other Bluetooth devices nearby
* It requires low power
* Does not require a line of sight like an infrared would
* People are able to use passwords to only allow certain people to connect
* It has a short range
* Not high bandwidth . Bandwidth measures of the capacity of a communications channel.
Bluejacking is a hacking method that allows a person to send anonymous messages to Bluetooth enabled devices .
GSM – Global System for mobile communication. It’s a digital mobile telephony system that is widely used in Europe.
GIS / GPS
GIS is a geographical information system designed to capture, store, manipulate, analyse, manage and present all types of geographical data .
GPS stands for Global positioning system which is a radio navigation system that allows users to determine their locations anywhere in the world .
The GPS was originally designed for the use of military and intelligence application in the 1960’s .
A GPS receiver must be locked onto the signal of at least 3 satellites to produce a 2D position – latitude and longitude. 4 or more satellites is needed to determine the 3D position – latitude, longitude and altitude.
GPS works by triangulation . It produces one circle on the map where the person is , then a second circle is made. Where these two circles cross over is the location of that person. Then another satellite signal is locked on to produce another circle , the person is where all 3 circles cross over. GPS is often used to get directions.
GPS advantages :
* Can be very accurate within 30cm with the right equipment
* No need for a paper map
* Is helpful for tourists to find places to visit
* Can offer many routes such as the fastest or Scenic
* Time is saved by not having to plan a route
* There’s a ‘home’ button so you don’t need to workout the route on the way back
* There’s many maps not just UK
* It can be difficult to set up a location
* Sometimes it can lead you down unsuitable roads
* May not recognize your location
* Tall buildings / forests can block the signal
* You need map skills just in case the GPS stops working
* Storms and bad weather affect the accuracy
* Maps need to be constantly updated.
NASA is developing a GPS system that will be augmented and improved to satisfy future military and civil requirements for accuracy, coverage, availability, continuity, and integrity.
GIS is used in Rwanda to help with healthcare. The digital maps are used to track and predict outbreaks of disease. They can help utilize the limited resources. For example; organizing clusters of disease and availability of drinking water.