hem with electrical tape. In SO doing, your primary concern is to ensure that each wire pair is correctly mated to the wire on the exten- sion. When you splice optical fiber, you must align the center core of one fiber to another, a much more difficult procedure. In addition, your options for joining fibers include welding or fusing, gluing, or the use of mechanical connectors. Each method is more time-consum- ing than simply twisting electrical conductors together and can result in an increase in cabling cost. This is especially true because personnel normally require training to splice optical fiber to minimize optical loss, which can adversely affect the transmission capability of a fiber. Welding or fusing normally results in the least loss of transmission between splice elements. However, you must clean each fiber end, then align and carefully fuse the ends using an electric arc. This is time-con- suming but can result in the least amount of signal loss between joined elements. Gluing or an epoxy method of splicing requires the use of bonding material that matches the refractive index of the core of the fiber. Thus, you just can't run out to the nearest CVS, Kmart, Office Depot, or another store and use any type of glue. Again, gluing is time- consuming and results in a higher loss of signal power than does fusing. A third method available to join fiber is the use of connectors. Although mechanical connectors considerably facilitate the joining of fibers, they result in more signal loss than do the other two methods and can reduce the span of the fiber to a smaller distance. Fiber Cost A second limitation associated with an optical transmission system is the cost of optical fiber. While you can compute the cost of fiber on a Introduction (bit/s)/km basis, which will always be less than that for copper cable, when used within a building, some organizations may require only a fraction of the capacity of the optical fiber. For this reason, it is often difficult to justify fiber to the desktop and similar applic