The most common type of cabling used for connecting
computing devices is known as twisted pair.
It's called a twisted pair cable because it features
pairs of copper wires that are twisted together.
These pairs act as a single conduit for information,
and their twisted nature helps protect against
electromagnetic interference and crosstalk from neighboring pairs.
A standard cat six cable has eight wires
consisting of four twisted pairs inside a single jacket.
Exactly how many pairs are actually in
use depends on the transmission technology being used.
But in all modern forms of networking,
it's important to know that these cables allow for duplex communication.
Duplex communication is the concept that
information can flow in both directions across the cable.
On the flip side, a process called simplex communication is unidirectional.
Think about a baby monitor,
where the transmission of data only goes in
one direction making it a simplex communication.
A phone call on the other hand is duplex since both parties can listen and speak.
The way networking cables ensure that duplex communication is possible is
by reserving one or two pairs for communicating in one direction.
They then use the other one or two pairs for communicating in the other direction.
So, devices on either side of
a networking link can both communicate with each other at the exact same time.
This is known as full duplex.
If there's something wrong with the connection,
you might see a network link degrade and report itself as operating as half-duplex.
Half-duplex means that, while communication is possible in each direction,
only one device can be communicating at a time.