Coaxial
Coaxial cable, or coax as it is commonly referred to, has been around for a long time. Coax found success in both TV signal transmission as well as in network implementations. Coax is constructed with a copper core at the center that carries the signal, plastic insulation, braided metal shielding, and an outer plastic covering. Coaxial cable is constructed in this way to add resistance to attenuation (the loss of signal strength as it travels over distance), crosstalk (the degradation of a signal caused by signals from other cables running close to it), and EMI (electromagnetic interference). Figure 2 shows the construction of coaxial cabling.
Figure 2 Coaxial cabling.
Networks can use two types of coaxial cabling: thin coaxial and thick coaxial. Both have fallen out of favor, but you might still encounter thin coax in your travels.