Telecommunications Essentials

Coaxial Cable

The second transmission medium to be introduced was coaxial cable (often called coax), which began being deployed in telephony networks around the mid-1920s. Figure 3.2 shows the components of coax. In the center of a coaxial cable is a copper wire that acts as the conductor, where the information travels. The copper wire in coax is thicker than that in twisted-pair, and it's also unaffected by surrounding wires that contribute to EMI, so it can provide a higher transmission rate than twisted-pair. The center conductor is surrounded by plastic insulation, which helps filter out extraneous interference. The insulation is covered by the return path, which is usually braided-copper shielding or aluminum foil-type covering. Outer jackets ...