Execute a Bing image search for the following devices:

Understanding Wired and Wireless Networks | 59 When it comes to interference, a cable itself can be its worst enemy. Generally, fiber optic cables are not affected by EMI, because they are inherently light based, not electricity based. Although a fiber optic cable will still produce a type of electromagnetic radiation, the cable is not traditionally affected by EMI in the same way copper-based cables are. However, if a fiber run is installed improperly, it can give strange results when it comes to the data signal. Exact installation rules must be followed including proper termination, specific radii for turns, avoiding bunching, and so on. Improper installation results in the signal becoming “bent,” which causes data loss. Chromatic dispersion is also a factor, as opposed to attenuation on twisted-pair cables. If the light is refracted too often, again, the signal will degrade. Fiber optic cable in general is the most secure cable, allows for the longest runs, and offers data transfer rates that are equal to or greater than twisted-pair cable. However, due to the com- plexity of installation, cost, and so on, fiber optic cable is not usually a first choice for all of the individual client computer runs. Instead, it is used for backbone connections; switch con- nections at the top of hierarchical star topologies, and other high-bandwidth or long-distance applications. CERTIFICATION READY How do you identify wireless devices? 1.4 ■ Comprehending Wireless Networks Wireless networks are everywhere. There are wireless networks for computers, handheld devices, wide-area connections, and more. Chances are you have used a wireless network in the past. In order to install and troubleshoot wireless networks, you must understand the basics of wireless communications and have knowledge of the devices, standards, frequencies, and security methods. THE BOTTOM LINE Table 3-3 continued C ABLING S TANDARD M EDIUM M AXIMUM D ISTANCE 1000BASE-BX10 Single-mode fiber 10 km 10GBASE-SR Multi-mode fiber 26–82 meters 10GBASE-LR Single-mode fiber 10–25 km 10GBASE-LRM Multi-mode fiber 220 meters 10GBASE-ER Single-mode fiber 40 km Identifying Wireless Devices Wireless devices might allow for central connectivity of client computers and handheld devices. Or, they might offer an extension of connectivity to a pre-existing wireless network and could be used to connect entire local area networks to the Internet. In addition, some wireless devices can be connected directly to each other in a point-to-point fashion. By far the most well-known wireless device is the wireless access point WAP. This device quite often also acts as a router, firewall, and IP proxy. It allows for the connectivity of various wireless devices such as laptops, PDAs, handheld computers, and so on. It does so by making connections via radio waves on specific frequencies. Client computers and handheld devices must use the same frequency in order to connect to the WAP. In the following exercise, we will identify wireless access points, wireless network adapters, and wireless bridges and repeaters.