requires a thick- er core. Another characteristic of glass fiber is its capability to support a relatively high signaling rate. Some types of single-mode step-index optical fiber can support a gigahertz signaling rate. Plastic Fiber Plastic-based fiber-optic cable is more durable than glass-based optical fiber. In addition, this type of optical cable is relatively inexpensive. How- ever, it is difficult to fabricate with a thin core; as a result, the plastic core and the plastic cladding are relatively thick. Typical plastic-based fiber- optic cable is manufactured as 480/550-, 735/700-, and 9800/1000-nm cable. Because a large core is prone to ray dispersion, plastic fiber-optic cable has the highest attenuation of the three types of material used for the construc- tion of fiber-optic cable. Currently, this type of optical fiber is used mainly for transmission over relatively short distances, such as within a factory. Understanding Optical Fiber Another problem with the use of plastic-based fiber-optic cable is that it is flammable, meaning that when used within a building, applicable codes may hamper its use and require its installation within a conduit. Plastic-Clad Silica As the term implies, plastic-clad silica (PCS) represents an optical cable manufactured using a glass core and a plastic cladding. The glass core consists of vitreous silica, while the plastic cladding is fabricated with a lower refractive index than in the core. The composition of a PCS-based optical cable is such that the attenua- tion and cost of PCS cable reside between those of a glass- and a plastic- based fiber-optic cable. A standardized PCS-based optical cable is 200/380 nm in size, with a 600-nm jacket. Although less expensive than glass, a PCS fiber-optic cable has considerable plasticity, resulting in difficulty when attempting to connect or splice cable. Because glass core fiber provides the lowest level of attenuation and high bandwidth, it is the preferred medium for both LANs and WANs. However, at data transmission rates as hi