Networking.docx

Magnetic or Chip Reader Magnetic stripes on plastic cards such as credit cards have been around for decades. More recently, credit card producers have been including an integrated circuit chip (ICC) in the cards as well, both as a security precaution and a convenience mechanism. These chips contain...

Magnetic or Chip Reader Magnetic stripes on plastic cards such as credit cards have been around for decades. More recently, credit card producers have been including an integrated circuit chip (ICC) in the cards as well, both as a security precaution and a convenience mechanism. These chips contain a combination of RAM, ROM, PROM, and a 16-bit CPU. Most retailers will have a magnetic reader or chip reader to make it easy for their shoppers to complete credit- or debit-based transactions. A card with an ICC is shown in Figure 3.48. If you’ve ever paid for anything with a credit or debit card, then you will be familiar with a magnetic reader or a chip reader. The only confusing part is knowing if you need to slide or insert the card, based on what the retailer requires. Readers are also made for smartphones and tablets, allowing commerce to happen anywhere a cellular connection can be made. 189 Figure 3.48 A plastic card with an ICC Plastic cards with embedded chips can store more than financial information. They can store things such as an employee ID, which a computer system can link back to security permissions, or other employee information. Often you will hear these cards referred to as smart cards. As more and more organizations discover the value in multifactor authentication for access to their computing assets, smart card readers have become indispensable as an instrument of the “something you have” principle. For quite some time, the United States government and its military forces have relied on common access cards (CACs), which serve as visual identification cards as well as chip-based smart cards. Businesses may validate employees by using a smart card reader, which is essentially the same machine that you will see in a retail environment. It attaches to the system internally or externally by USB or sometimes through a dedicated adapter. The reader provides power for the chip that is embedded in the smart card. 190 The chip on a smart card may contain one or more public key infrastructure (PKI) certificates. Smart card readers used by the United States Department of Defense are able to access the CAC’s ICC in order to use an identification certificate in the chip to verify the identity of the bearer. A PIN, however, may still be required to establish two-factor authentication. In other uses, card readers access digital-signature and encryption certificates to establish nonrepudiation and confidentiality for a user during electronic exchanges of information. NFC/Tap Pay Device At some point, someone decided that having to swipe or insert a credit card to buy something was way too much work. Why couldn’t people just wave their payment method in the general vicinity of the retailer to complete the transaction? This is where NFC and tap pay devices come into play. They are natural extensions of the smart cards discussed in the previous section. A tap pay device works on the concept of near field communication (NFC). The embedded chip in the card is activated by a radio frequency signal when it comes within a certain distance of the reader—the maximum range is usually about 3″. Depending on the implementation, the user may need to actually tap their card to the reader, or they may be able to just get it within range. The activated chip transmits the credit card number to the reader, which is connected to the retailer’s point of sale terminal to complete the transaction. This makes completing transactions faster than swiping or inserting a card. To improve security, some transactions require the user to enter a preset PIN. Also note that some countries limit the amount that can be spent using a tap pay or NFC device. The other thing that this technology enables is the payment with smartphones. No longer do shoppers have to carry around a credit card! Apple Pay and Google Pay both allow users to enter credit card information into their phones, and then use the phone to pay at an NFC or tap pay terminal. Most of the time, authorization is required using the touch sensor on the phone to validate a fingerprint. Printer Often immediately behind your monitor in output-device importance, the one or more printers that you have attached to your computer become invaluable when you need to produce a hard copy for distribution or for inclusion in a report, for instance. Chapter 5, “Installing and Configuring Printers,” details the various printer families, such as impact, thermal, inkjet, and laser, as well as the details involved in their installation, including connectivity and driver installation. Scanner One of the earliest input devices aside from the keyboard and mouse was the scanner. Today, it’s somewhat unusual to find a stand-alone scanner. Most are integrated into a multifunctional printer or copy machine. Like printers, scanners use USB, Wi-Fi, or Bluetooth to connect. 191 Scanners use light to reflect off of a surface and measure the relative reflections of the different dots that make up the grid that the scanner is able to detect. The tighter the grid (the more dots per inch [DPI] supported), the higher the resolution of the resulting image. Charge-coupled devices (CCDs) are a common choice in today’s scanners. CCDs convert the light they receive into electrical impulses, which are then forwarded to the software producing the scan for further processing into an image that is a facsimile of the original object being scanned. A flatbed scanner evokes the concept of a copier with the paper handling and printing mechanisms missing. This image is not far off, which is why copiers make wonderful scanners, as long as they can produce a digital image file. It’s also why multifunction devices are so prolific; it takes very little to outfit a printer with a scanner component to be used for input to the computer and as a fax-scanning device. Inbound faxes can be printed, or the same digital interface that the scanner uses can be used to transfer the image electronically to software in the computer. Figure 3.49 shows the top flatbed scanner portion of a laser multifunction device that provides a way to print, scan, and fax. Figure 3.49 A flatbed scanner Many multifunctional printer/scanner combinations designed for the workplace have an automatic document feeder (ADF) attached to the top. This allows a user to place several sheets of paper in the ADF and have them all copied or scanned at the same time. Contrast this with a flatbed scanner, which can scan only one piece of paper at a time. Figure 3.50 shows one of numerous brands of portable document scanners. These handy little devices are scarcely more than a foot long and can make short work of scanning192anything from a business card to a gas receipt to an 8.5″ × 11″ lodging folio. The associated software that comes with these scanners performs optical character recognition (OCR), and it can recognize the orientation of the text and glean pertinent information from the documents scanned to populate the internal database. From this database, you can produce reports for such purposes as expenses, invoicing, and taxes. This model also offers the option to create a PDF during the scan instead. Figure 3.50 A portable document scanner KVM Switch A KVM switch isn’t an input or output device, per se, but it allows you to switch between sets of input and output devices. The KVM switch is named after the devices among which it allows you to switch. The initials stand for keyboard, video, and mouse. KVM switches come in a variety of models, with different connector types available. The purpose of the switch is to allow you to have multiple computers attached to the same keyboard, monitor, and mouse. You can use these three devices with only one system at a time. Some switches have a dial that you turn to select which system attaches to the components, while others feature buttons for each system connected. Common uses of KVM switches include using the same components alternately for a desktop computer and a laptop docking station or having a server room with multiple servers but no need to interface with them simultaneously. Figure 3.51 shows an older, four-system VGA/USB switch with analog audio switching as well. If DVI or other attachments are desired, adapters are required. The buttons on the front (right side of the image) switch the common console connections among the four systems, only three of which are currently attached. A maximum of one193of the four LEDs beside the corresponding buttons is lit at a time—only for the system currently in control. Figure 3.51 A KVM switch Storage Devices We’ve already spent quite a lot of time in this book discussing storage options, such as optical drives and hard drives. These devices are frequently internal to the case, but external options are available as well. Take optical drives, for instance. In order to save space on smaller laptops, manufacturers are removing optical drives. If users want to play a Blu-ray or DVD movie, they will need to attach an external optical drive. External optical drives can be used for data backups as well. These external drives will most likely connect via USB or eSATA. External storage drives can greatly enhance the storage capacity of a computer, or they can provide networked storage for several users. A plethora of options is available, from single drives to multi-drive systems with several terabytes of capacity. Figure 3.52 shows an external network-attached storage (NAS) device. 194 Figure 3.52 A network-attached storage device  “NETGEAR ReadyNAS NV+” by PJ - Own work. Licensed under CC BY-SA 3.0 via Wikimedia Commons Looking at Figure 3.52, you can see that this is a self-enclosed unit that can hold up to four hard drives. Some hold more; some hold less. Nicer NAS systems enable you to hot-swap hard drives and have built-in fault tolerance as well. In addition to the hardware, the NAS device contains its own operating system, meaning that it acts like its own file server. In most cases, you can plug it in, do some very minor configuration, and have instant storage space on your network. As far as connectivity goes, NAS systems will connect to a PC through a USB or eSATA port, but that is primarily so you can use that PC to run the configuration software for the NAS. The NAS also connects to the network, and that is how all of the network users access the storage space.