tailieunhanh - CompTIA Network+ Certification Study Guide part 11

CompTIA’s Network+ certification Study Guide part 11 is a globally-recognized, vendor neutral exam that has helped over 235,000 IT professionals reach further and higher in their careers. The 2009 Network+ exam (N10-004) is a major update with more focus on security and wireless aspects of networking. Our new study guide has been updated accordingly with focus on network, systems, and WAN security and complete coverage of today’s wireless networking standards. | 86 CHAPTER 2 Network Media IEEE1394 FireWire If you ve ever hooked up a digital camera digital video DV camera or other devices that need to transfer large amounts of data to your computer you may have used FireWire. FireWire is a proprietary name for an external bus that supports fast data transfer rates. Apple Computers originally developed the technology but it has since been standardized as IEEE1394. Since then other companies have developed their own trademark names including Sony s iLink. Devices that follow IEEE1394 allow data to be transferred at 400 Mbps in IEEE1394a and 800 Mbps in IEEE1394b . In addition to this it allows a single 1394 port to have up to 63 external devices connected to it. It is similar to USB in that can provide power to a device and supports both plug and play and hot plugging. Wireless Media As we discussed briefly in the previous chapter and will discuss in greater detail in Chapter 4 wireless networks require minimal cabling. Data is transmitted over the air using wireless adapters and wireless routers so little to no cabling is required for network communication. Transceivers Media Converters The term transceiver is short for transmitter-receiver which also describes its purpose on a network. Transceivers are the portion of a network interface that transmits and receives electrical signals across the transmission media. They are also the part of the interface that actually connects to the media. Transceiver types can be classified as being either on-board which are built onto a network card or external. With an external transceiver the actual media connection is made external to the NIC using a small device that attaches via an extension cable to the NIC. The types of transceivers and media that can be served by a NIC determine the appropriate connector and as we saw earlier in this chapter each media type has a typical connector type or connection method. One such connector is an AUI connector which is also called a DIX .