2.1 Media Characteristics
Media is used to carry data signals from sender to receiver. Media can be categorised as guided or unguided.
Guided media refers to the guiding of waves along a physical medium, such as, copper cable or fibre-optic cable.
Unguided media provides the means of transmission but does not guide the electromagnetic signals. This type of transmission is normally referred to as wireless transmission and transmission can be achieved through air, water and space.
The most common type of cable used in data communications is copper. There are different types of copper cable but they all share the feature of transmitting data as an electrical signal. This gives rise to one of the weaknesses of this type of media, which is that sending an electronic signal causes heat that is absorbed by the media as the signal travels thus causing signal loss, i.e. attenuation. The faster the data transfer rate over copper cable the greater the possibility of signal loss and interference.
Developments in cable technology are aimed at increasing reliability and minimising data loss.
There are two main categories of copper cable:
- Twisted pair