Internet Connection Mediums

(Asymmetric / Symmetric) Digital Subscriber Line

DSL and ADSL internet connections operate over the copper telephone line that you might find in your house.

This works by something called multiplexing, where through the magic of technology, several streams of data (ie voice, and internet) can be combined and transceived (To transmit and receive) over one connection!

In the case of DSL connections, the voice data is multiplexed with the network data by having the lower frequency spectrum allocated for voice data, and the upper frequency spectrum allocated for network data.

Therefore, to extract the voice data a low-pass filter can be applied to strip the network data.
Likewise, to extract the network data, a high-pass filter can be applied

This is done in a device called a DSLAM, or Digital Subscriber Line Access Multiplexer, often located in telephone exchange buildings. These devices split the voice and network data, and route them into the telephone network or data network.

The 'A' in ADSL

As the bandwidth available over a telephone line is quite limited, the telephone gods decided to allocate more of the bandwidth spectrum for downstream reception rather than upstream transmission - As most people are consumers of data, rather than producers.

As consequence, the Asymmetric Digital Subscriber Line technology was born

Cable

Cable internet (currently being phased out because of the nbn) is a technology which uses coaxial cable (those things you used to connect to TVs) as the transfer medium.

For coaxial cable users, bandwidth is shared - the more users on the network, the less bandwidth you are given (RIP peak hour).

Frequency division multiplexing is used (you are allocated a frequency range, and another household is allocated a different frequency range).

Fiber

Who knows.
It’s fast (or meant to be).
The nbn does this (or at least they’re meant to be).
Eh.