564. Cut the top of the wires even with one another and insert the wires into the RJ-45 connector.Make sure the wires extend to the front of the RJ-45 connector and make good contact with themetal contacts in the RJ-45 connector and in the correct order.5. Crimp the RJ-45 connector with the crimping tool until you hear a click.6. Use a cable tester to verify the connectivity of the cable.Optical fiberOptical fibers feature low loss and long transmission distance.Optical fibers can be classified into single mode fibers and multi-mode fibers. A single mode fiber(with yellow jacket) carries only a single ray of light; a multi-mode fiber (with orange jacket) carriesmultiple modes of lights.Table 41 Characteristics of single mode and multi-mode optical fibersItem Single mode fiber Multi-mode fiberCore Small core (10 micrometers or less) Larger core than single mode fiber (50micrometers, 62.5 micrometers or greater)Dispersion Less dispersion Allows greater dispersion and therefore,signal loss exists.Light source andtransmission distanceUses lasers as the light source oftenwithin campus backbones for distanceof several thousand metersUses LEDs as the light source often withinLANs or distances of a couple hundredmeters within a campus networkTable 42 Allowed maximum tensile force and crush loadPeriod of force Tensile load (N) Crush load (N/mm)Short period 150 500Long term 80 100Fiber connectors are indispensable passive components in an optical fiber communication system.They allow the removable connection between optical channels, which makes the optical systemdebugging and maintenance more convenient. There are multiple types of fiber connectors. Figure43 shows an LC connector.Figure 43 Appearance of an LC connectorFollow these guidelines when you connect an optical fiber:• Before connecting an optical fiber, make sure the connector and cable type match the interfacemodule.• The fiber Ethernet port of the firewall supports only the LC connector.• Fiber connectors are fitted with dust caps. Keep the dust caps secure when the fiber connectorsare in use. Install dust caps when the fiber connectors are not in use to avoid damage to theirend face. Replace the dust cap if it is loose or polluted.