# Coaxial Cable ## What is Coaxial Cable Coaxial cable, commonly called coax, is a type of electrical cable that has been used in networking and telecommunications for many decades. It consists of a central copper conductor surrounded by a layer of insulating material, which is in turn surrounded by a cylindrical metallic shield, and finally covered by an outer insulating jacket. The inner conductor carries the signal, and the outer shield acts as both a return path for the signal and a barrier against electromagnetic interference from the environment. ## Structure of Coaxial Cable The center conductor is a solid or stranded copper wire that carries the electrical signal. Surrounding the center conductor is a dielectric insulator, which is a material that does not conduct electricity. This insulator maintains a consistent spacing between the center conductor and the outer shield. The outer conductor is typically made of braided copper wire or metallic foil and serves as both the return path for the current and as a shield that blocks external electromagnetic interference. The outer jacket is a plastic covering that protects the cable from physical damage and moisture. ## Types of Coaxial Cable Thick Ethernet, also called thicknet or 10BASE5, used coaxial cable with a diameter of about 1 centimeter. This was one of the earliest Ethernet standards and allowed cable segments up to 500 meters long. Thin Ethernet, also called thinnet or 10BASE2, used thinner coaxial cable that was easier to handle. It allowed segments up to 185 meters. Both of these types have been obsolete for many years, replaced by twisted pair Ethernet. RG-6 coaxial cable is the type currently used for cable television and cable internet services, as well as for satellite television connections. RG-59 is an older and thinner coaxial cable used in some closed-circuit television systems. ## Applications of Coaxial Cable Although coaxial cable has been largely replaced by twisted pair cable for Ethernet networking, it remains in widespread use for cable television distribution, cable modem internet service, satellite television, antenna connections for radio and television, and some closed-circuit television security systems. ## Advantages and Disadvantages Coaxial cable provides better shielding against electromagnetic interference than unshielded twisted pair cable. It can transmit signals over longer distances than twisted pair. The disadvantages include higher cost and less flexibility compared to twisted pair, making it more difficult to install and route through buildings. For Ethernet networking, twisted pair cable has become the standard choice because it is cheaper, more flexible, and supports the speeds needed for modern networks.