Continuing next with data communications definitions let us cover some Fast Ethernet specifications and definitions.
Coaxial cable (coax) was commonly used for thick ethernet, thin ethernet, cable TV and ARCnet, coaxial cabling that uses BNC connectors; heavy shielding protects data, but expensive and hard to make connectors
Through the first half of the 1980s, Ethernet's 10BASE5 implementation used a coaxial cable 0.375 inches (9.5 mm) in diameter, later called "thick Ethernet" or "thicknet". Its successor, 10BASE2, called "thin Ethernet" or "thinnet", used a cable similar to cable television cable of the era.
10BASE5, also called Thicknet or Thick Ethernet, uses thick, coaxial cable. Thick coax cable (RG-6) requires the following:
10BASE2 uses thin Ethernet cable. Thin coax cable, or Thin Ethernet, implemented with T-connectors and terminators, such as RG-58 and A/U or C/U, have the following specifications:
A British Naval Connector (BNC), also known as the Bayonet Nut Connector, also known as Bayonet Neill-Concelman (the inventors of the BNC connector) is usually used for thinnet coaxial cable. A terminator is a resistor attached to the end of the cable. Its purpose is to prevent signal reflections, effectively making the cable "look" infinitely long to the signals being sent across it.