How does the connection work from home?

Connecting using an ISP

An ISP, or Internet Service Provider, is a company that provides you with a point of access to
the Internet. When you connect to your ISP, your computer (or your own network) becomes an
extension of the Internet itself whilst you remain connected.

To connect from home you need several things. Apart from a computer (obviously!) you'll need
a phone connection, a modem or ADSL router, and some Internet software. Things will be easier
if you're using a relatively recent operation system, such as Windows Vista/XP or MacOSX, but
it's possible to connect with older or more obscure systems.
With a modem and the appropriate software, you can dial up another modem connected to another
computer, and establish a network connection with it. Usually, this computer is linked into the
Internet, and so you're online.
With an ADSL modem or router, a similar procedure happens, but a filter splits the telephone
line into voice and data (low and high frequencies) and your router negotiates a connection with
the ADSL equipment in the telephone exchange.

Frequencies used on an ADSL line: PSTN is the normal telephone ("voice") usage, and the
upstream/downstream areas are for data. Note the unequal proportions of the data range (i.e.
Assymetric DSL
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