home and personal communications how computers connect to the internet computing department1

Computing Department 1

Home and Personal Communications

How computers connect to the Internet


The Internet

• No innovation in recent years has had more impact on the way we live than the Internet

• It has changed the way we perform daily tasks forever

• But what is it?• “The Internet is a global network of computers

that can communicate with each other (i.e send and receive data)”



• Any computer can connect as long as they have the correct hardware and software, but you also need an ISP (Internet Service Provider). An ISP has powerful computers called servers which are permanently connected to the Internet

• Most ISP charge for their services• Other software needed is a browser such as

Internet Explorer.



• Computers can connect to the Internet in a number of ways:

Dial Up

Broadband

Cable – Fibre Optic

Satellite

Mobile Comms (4G/Wifi)

Tethering


Dial-Up Internet

• Dial up internet is an extremely slow internet connection.

• 56kbps (roughly 0.5mpbs).

• Requires a phone-line and a modem on your computer.

• Dial’s your ISP to make a connection.

• Converts signal into one that can be passed down a phone line

• Cheap

• Not suitable for downloading music etc (an average song would

take around 1-2 hours to download!)


Satellite Internet

• Useful for users where standard internet (broadband / cable) is

not available such as rural areas where cables cannot be laid

• Available world-wide

• Some delay when using the connection, making it a bit “laggy /

jumpy.”

• Not suitable for online games or advanced use like “remote

surgery”

• Suffers from “rain fade.” Signal deterioration from moisture.


Broadband

• Fast connection via ISDN and ADSL• ISDN has been replaced generally by ADSL (Asymmetric

Digital Subscriber Line) which uses a nationwide network of digital connections. This system uses digital signals compatible with computer signals so there is no need for a modem

• ADSL uses existing phone lines to connect. • Can use phone at same time as connection to Internet• Can use webcam services• Watch video/listen radio in real time• Several devices can connect at same time


Cable

• Fibre optic cables provide broadband as well as TV and telephone

• Generally faster than ADSL• Reliable• Constant high speed link• Expensive


Mobile CommunicationsWi-Fi


Mobile CommunicationsWi-Fi

• Allows you to share a broadband connection.

• No need for lots of wires.• Can access the web on a range of appliances (phone, TV, games console

etc). Let’s everything ‘talk’ to each other.

• Secure (if protected)

• Requires wireless equipment.

• Can ‘conflict’ with surrounding devices.• Could be hacked? Security / Transmission interception.• Wireless Router Needed.• Can share information, music etc.• Hot spots


WI-FI

• Advantages:– Not restricted where you work– Work on the move– No wires– Many Devices can connect

• Disadvantages:– Can be less secure/hackers– Black spots & Limited to distance from source of

transmission


Bluetooth

Method used to transfer data over short distances from fixed/mobile devices

• Uses Radio Chips

• Uses little power.• Instant configuration. Simply scans and find a name.

• Enter a pin to securely connect.

• No in-line of sight. You do not have to be sat next to

someone.


Bluetooth

• Any device can communicate together if they

have Bluetooth.• Relatively slow connection of 1Mbps, compared

to infra-red.• Bluetooth can open the door for security

breaches, once access is granted.• Potential for transmission to be intercepted.• Illegal transmissions (music etc)


Bluetooth

• Uses:– Wireless keyboards and mice– Wireless headphones– Printing– Wireless headsets– Games like the Wii


BluetoothAdvantages:• Speed: Can send/receive data/images/music/text instantly.• Cost: Can send/receive data/images/music/text for no extra cost. • No wires are needed/wireless.• You can synchronise devices/link devices.• Hands free (while driving).• Security: Pairing requires PIN.Disadvantage:• Can only be used over short distances.• Relatively small bandwidth / slow to transfer large files. • Cannot send to a group / can only handshake with one device at a time.• Runs battery down quickly.• Can be used for hacking.


Mobile Communications

• 3G /4G

– Accessing the internet / using data connection via mobile technology.

– Can be via mobile phones. Can be on computer using a USB ‘dongle’ often provided by

phone providers.


G.I.S

• “A Geographic Information System (GIS) is a collection of computer hardware,

software and geographic data used to analyse and display geographically referenced

information.”

• Put simply:

– A system which combines a geographical map, along with additional

information, such as:

• Facilities in that area.

• Buildings / landmarks.

• Speed / traffic information

• Optimal routes when driving.


Mobile Phone applications


Satellite Navigation


Google Earth


Other examples:

• Multimap• AA route finder


GISAdvantages• Can select / plan the shortest route from A-Z / real time guidance of route• Can share position with others• Can see bird’s eye view of your house• Can be found by others if lost/in an emergency • Can track / be tracked / locates where you are • Can find places of interest / petrol stations, etc. • Can locate exactly where your photos have been taken• Locate your device• Can locate weather for your particular area / Can predict weather more accurately• Online mapping / look at maps• Walking toursDisadvantages:• Can send you down a route you would not normally drive/ too narrow• Can be difficult to use/get used too• Data can be out of date/has to be updated• Can cause accidents if input information whilst driving and become distracted• Problems with loss of Satellite signal• Drains battery quickly

home and personal communications how computers connect to the internet computing department1

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