Page 246 - Informatics_Practices_Fliipbook_Class12
P. 246

An Ethernet card makes it possible for two systems on a network to communicate with each other. The most common
        connector used with Ethernet cards is RJ-45. Figure 6.15 depicts the Ethernet card going internally to the motherboard.
        The RJ-45 connector will go inside the RJ-45 LAN port shown in the figure and the activity LEDs are lit when the device
        is communicating with the Ethernet network connected with it.



                                    Metal Expansion Slot Bracket








                                Activity LEDs
                                      RJ-45 LAN Port




                                                  Figure 6.15 Ethernet Card

        WiFi Card

        A WiFi card provides wireless connectivity and is used to form wireless LANs. Systems with WiFi cards can connect
        wirelessly to networks. Figure 6.16 depicts two types of WiFi cards: (a) Internal (installed internally on the motherboard)
        and (b) External (usually inserted in the Universal Serial Bus (USB) port). Communication in a wireless network occurs
        via radio waves. A router with one or more antennae is required for a wireless network to function. A PCI-Express WiFi
        card is often installed on the motherboard of a desktop computer.

























                              (a) Internal WiFi Card                      (b) External WiFi Card
                                                    Figure 6.16 WiFi Card

        6.5.3 Repeater

        With an increase in distance, the strength of the signal decreases. A repeater intensifies the strength of the incoming
        signal before transferring it further. As a repeater restores the strength of a signal, it is also called a regenerator. A
        repeater is required when the length of a network cable exceeds a particular distance. For example, if the medium
        is a twisted pair cable, a repeater is required after every 100 metres (328 feet). Suppose a signal can travel only 100
        metres, so connecting three cables with repeaters will enable the signal to cover 300 metres. In Figure 6.17, we show
        the use of the repeater.


          232  Touchpad Informatics Practices-XII
   241   242   243   244   245   246   247   248   249   250   251