25-08-2017, 09:32 PM
Connecting to the Internet.
Connecting to the Internet.ppt (Size: 190.5 KB / Downloads: 28)
Methods available
There are a number of ways of connecting to the internet. These include:
‘Dial-up’
Integrated Subscriber Digital Line (ISDN)
Broadband (ADSL)
Mobile devices (e.g. latest mobile phones)
Dial-up connections
The original telephone system is based on ANALOGUE technology. Analogue signals change smoothly with time. Like this:
Your voice is ‘analogue’ in form – it changes smoothly and so this technology was perfect for carrying telephone conversations.
Dial-up connections
Modems are defined by their speed i.e. how many bits per second can they handle.
A modern dial-up connection makes use of a 56 Kilobits per second Modem.
A dial-up connection allows you to connect to the internet via a local server using a standard 56k modem, your PC literally dials (hence the name) a phone number (provided by your ISP) and connects to the server and therefore the internet.
Disadvantages of Dial-up
56Kb is very slow by modern standards. A graphic heavy web page can take tens of seconds to load. WWW even had another joke meaning: the World Wide Wait!
Dial up ties up your telephone line and so it cannot be used for anything else.
It takes a while for the computer to set up a connection i.e many seconds.
Internet Service Providers may charge you by the minute and so a slow link means you pay more.
ISDN - disadvantages
Your main telephone socket has to be changed to an ISDN box by an engineer.
Your computer has to be fitted with an ISDN modem which is more expensive than a standard modem.
It is more expensive than Dial-up on a monthly basis.
Should you move house, you have to pay for your telephone line to be converted back again to a normal line.