JACKET SHIELD DIELECTRIC INSULATION CONDUCTOR Advantages of coaxial cabling are as follows: Low susceptibility to electromagnetic interference resulting in less interference and crosstalk. High bandwidth for transmitted signals, with resulting lower signal distortion. Can be used over longer distances than twisted-pair cables. Can be matched to operate with twisted pair through the use of a device called a balun. Lower signal distortion. More channels can be transmitted over the same cable than with twisted pair. There is less of a tendency to have crosstalk between cables than with twisted pair. There is greater security of the information than with twisted pair. Disadvantages of coaxial cable are as follows: It is more difficult to install than twisted pair, costing more and taking more time. It is heavier and fatter than either twisted pair or fiber op- tic cable. The Telecom Handbook 13 257 CABLE Many systems have shifted from coaxial cable to twisted pair as new technology is developed to improve the transmission on the twisted pair. It must be installed in either a daisy chain fashion or home run, SO it does not have the flexibility of twisted pair. Fiber Optic Cable Fiber optics is a technology in which light is used to trans- port signals from one point to another. Fiber optics are thin filaments of glass through which light beams are transmitted. (See Figure 12.5 and Figure 12.6) Single mode fiber optic cable is used under the streets to con- nect one telephone company central office to another, for example. It uses lasers as a light source and can transmit a signal for 100 miles without a boost. Multimode fiber optic cable has a much larger core diameter than single mode. It typically used within a building, uses LED's (light emitting diodes) as a light source and transmits signals much shorter distances than single mode. There are two types of multimode fiber optic cable. One is multimode step index. This is sufficient to handle the speed of ethernet and token ring LAN transmissions. Multimode graded i