Laptops All-in-One Desk Reference For Dummies- P56 potx

Book VIII Chapter 3 Working a WiFi Network 527 802.11g also works with machines that support 802.11b or 802.11a; going the other direction, though, an 802.11a transceiver in a laptop or

Seeing Hot Spots 524

Seeing Hot Spots

It used to be that the business and tourist traveler expected a hotel to deliver

a clean place to sleep, a vending machine in the hallway, and a television to keep us amused I still appreciate a comfortable bed, but today many travel-ers have a new requirement in second place on their list: WiFi

Hotels have come to realize that for a relatively small investment they can install wireless access points in their buildings to make happy those of you — the readers of this book — who travel with a laptop as a constant companion

In many places, this access is free — part of the cost of the room, just like the basic cable service to the television Some hotels charge a fee for access, although that may put them at a competitive disadvantage if the place across the street provides WiFi for free

A similar trend has developed at many coffee shops and other casual eater-ies; they have come to realize that they can differentiate themselves from their competitors by enabling a WiFi network along with their double cinna-mon dolce lattes (Acinna-mong eateries offering free service is Panera Bread Company.)

You’ll also find free Internet access at many public libraries and in some public buildings

There are also services that offer hourly, daily, or monthly subscriptions to WiFi access In most such setups you can turn on or off your account any time you need to do so Companies like T-Mobile, a major cell phone service provider, offer subscription plans to WiFi at many Starbucks, Borders Books, FedEx-Kinko’s, and other locations

You can also visit national web sites that allow you to search by airport or ZIP code; most of these will give you the locations for paid commercial access One such web site is www.jiwire.com

Think of the things we take for granted today: cell phones, Web-connected personal data assistants, and Internet cafes Although early mobile and cell phones started out using analog signals, by now nearly all the people walk-ing around talkwalk-ing into their hands are exchangwalk-ing digital information Most modern cell phone systems are now digital Many cable television serv-ices transmit programming digitally And within the next decade, most of the

“old” analog broadcasts will convert to digital radio and digital television (Unless there’s a last-minute reprieve, analog television broadcasts come to

an end in February of 2009.)

Book VIII Chapter 3

Seeing Hot Spots 525

Which brings you to laptops and what has become generically known as

WiFi The term itself is a geeky play on words, meaning Wireless Fidelity Way

back in the early days of recorded music on large, heavy platters we passed through a period where the quality advanced to High Fidelity, or HiFi I’m telling you this because I like to explore the derivation of words and terms, but trust me: call it WiFi (pronounced why-fie) and keep it to yourself how you ever knew how it came to bear that name Even the geekiest of geeks would look at you oddly if you were to ask for the location of the nearest Wireless Fidelity hotspot One common industry icon for WiFi technology is shown in Figure 3-1

Allow me to give you an analogy

It took almost 20 years before computer design-ers updated an older wonder technology for use

in the modern world: it’s called radio The first use of radio waves to transmit information was more than a century ago: 1887, to be precise, when the first experiments in transmission of what came to be known as Morse Code were sent from one spot to another without wires

Interestingly, Morse code was essentially a binary code: it had only two characters, a short click or tone and a long click or tone These dots

or dashes symbolized letters which could then

be strung together to form words and sen-tences The letter S was dot, dot, dot; the letter

O was dash, dash, dash

However, from more than a century, these codes and then the audible words and music of broad-cast radio and eventually television were created through the use of an analog signal transmitted

as electrical waves In one form the waves con-veyed information by variance in height or size;

this was AM or amplitude modulation radio In another form the signal delivered sound or pic-tures by varying the frequency or length of the waves; this was FM or frequency modulation

Either way, radio was analog, as in an analogy of the information Think of this: a high tone or a loud

sound was represented by its analog in the form

of a high wave in an AM signal

The first computers (and some current com-puters) still used analog signals For you young-sters out there: We used to communicate over the telephone using a modem that warbled out

an annoying chatter or varying tones Our com-puters, which worked internally by manipulat-ing digital information, would send data to a modem (a modulator-demodulator) that would convert the digital information into an analog signal that would travel like an electronic voice over the telephone to another modem that could convert the warbles back into 0s and 1s

This worked reasonable well because telephone technology was designed to carry sounds

“Hello, Joe’s Pizzeria” is a sound, just as the indi-vidual warbles that represented 0s or 1s of binary codes were sounds

But modern technology finally caught up If, in commercial radio’s Golden Age in 1947 we lived

in a cloud of signals, by 2007 we were in a dense fog of radio waves getting thicker minute by minute

The acceleration of radio use has come about with a switchover from analog waves to digital signals

Seeing Hot Spots 526

Courtesy Toshiba America, Inc

The correct name for the technology that underlies WiFi is (for the moment,

and for most systems) one of several variations of 802.11 The Institute of

Electrical and Electronic Engineers (IEEE) helps simplify (Ha! You say?)

tech-nology by setting up committees to determine standards that various com-panies can then adopt for their products They use numbers for their standards, and the ones that apply to WiFi are in the group called 802.11 At this time there are four flavors of 802.11 in common use, and they are demarked as subsets of that numeric name: a, b, g, and n

As this book goes to press, 802.11n is the next new thing, supplanting 802.11g, 802.11a, and the comparatively ancient 802.11b Each standard is

downwardly compatible with earlier sets of code Here’s what that means:

Figure 3-1:

The computer industry’s symbol for WiFi can

be found

on laptop hardware and net-working devices as well as in some onscreen utilities

Back to analog

Musical purists and old-school photographers bemoan the very subtle subtleties they claim to

be able to detect between an analog record and a digital CD or between a film and photo-graphic paper print and a digital image They are probably correct, because in theory there can be an infinite range of differences between

a particular note or color in an analog world

while the distinction between tone or color number 23643 and 23644 is forever fixed However, there is little likelihood we will revert from digital to analog in most applications and I’m not convinced that most mere mortals can see or hear colors or tones that lie between finite digital values

Book VIII Chapter 3

Working a WiFi Network 527

802.11g also works with machines that support 802.11b or 802.11a; going the other direction, though, an 802.11a transceiver in a laptop or a router for such a system will only operate at that slower, weaker technology and isn’t downwardly compatible with anything else

Digital communication has a number of advantages over analog:

✦ Precision If computer designers agree that the code 83 (or 1010011 in

binary) stands for “S” or that a color made up of Red 242, Green 30, and Blue 70 represents a rich but not gaudy shade of red we have a very high probability that a properly set up electronic device will reproduce exactly that letter or color

✦ Accuracy When we speak words to each other there is a great

possibil-ity we may misunderstand what we hear; it is much less likely that a computer system will misread a 0 for a 1, and the computer “words” can include error-checking algorithms that correct for errors or request a retransmission

✦ Economy Digital signals, because they consist of just 0s and 1s, require

a much narrower “band” in the radio frequency This allows more and more signals to squeeze into the spectrum without interfering with each other

✦ Speed With the advance of technology and the increasing demands of

the marketplace, engineers have found better and better ways to pump more and more digital data at higher and higher speeds across radio signals

✦ Locality Carefully designed hardware, coupled with advanced security

features, allow millions of WiFi systems to coexist in a community or a region or a state without interfering with each other even if they use the same radio frequency When I turn on my laptop in my office I usually can see at least three other wireless local area networks in my very rural neighborhood; the password protection on my router keeps outsiders from getting into my system and keeps me out of my neighbor’s networks

Working a WiFi Network

Nearly everyone has greatly enjoyed the experience of flying the friendly

skies from one place to another In general, that means we get to use a

hub-and-spoke scheme: To get from Boston to San Diego, for example, you might

fly from Boston to Dallas and then meet up with people from all over the country who get off their incoming planes to join you on a flight from Dallas

to San Diego

In the airline example, the hub (Dallas, in this case) receives incoming pas-sengers, gathers them together in groups, and then transmits them to their destination Coming back, the same process occurs in the other direction

Working a WiFi Network 528

Enough about airlines; I love flying and hate airports But the same general principle applies to a WiFi network

The signals from your laptop (or from a desktop or other electronic device with wireless capabilities) are transmitted in a more or less circular pattern throughout your home or office or other workplace Somewhere within the reception range of the signal, a wireless router serves as a hub for those signals

The router can serve several purposes:

✦ It can be the gateway to a broadband Internet connection, allowing one

or more wireless devices to send signals and receive responses for that purpose

✦ It can be the access point to a single desktop computer, allowing inter-change in both directions with the wireless computer

✦ It can accept signals from a wireless device and move them along to a printer

✦ It can be the hub that allows interchange of data between and among a large number of wireless devices You can connect one laptop to another, or a laptop to a desktop, or establish a wireless network that serves an office full of electronics

What’s the frequency?

A higher frequency generally travels a shorter distance, which makes it a good choice for local area networks; at the same time it can carry more data than a signal sent at a lower frequency

Inside a WiFi network

A WiFi communications system is similar to other radio technologies including walkie-talkies and cell phones However, 802.11 devices are designed for relatively short-distance, higher-speed work

One important difference: WiFi operates in a high-frequency band of 2.4 GHz or 5 GHz Com-pare that to AM radio which is relegated to the

radio space between 530 and 1710 KHz in North America, and FM which operates between 87.5 and 108 MHz K stands for a thousand, M for a million, and B for a billion And Hz: That means the number of cycles per second, measured in Hertz and named after German physicist Heinrich Hertz who made some important discoveries and demonstrations of radio waves in the 1880s

Book VIII Chapter 3

Working a WiFi Network 529

Devices that operate in the 2.4 GHz band may suffer from interference caused

by common office and household appliances including cordless telephones, microwave ovens, and wireless baby monitors Engineers attempt to compen-sate for this by designing WiFi systems to work on any of three frequency

bands within their allocated range, and they can also frequency hop rapidly

between the different bands to deal with interference and permit multiple devices to use the same wireless connection simultaneously

Bluetooth wireless devices, used by some laptops, cell phones, and personal digital assistants, also operate in the same 2.4 GHz range but are less likely

to cause or suffer from interference because they use a scheme called

fre-quency hopping spread spectrum signaling As the name implies, this spreads

a signal across multiple frequencies

802.11a and the developing 802.11n specifications use the 5 GHz band, which

is less crowded with household appliances and also offers eight nonoverlap-ping channels as opposed to the three in the 2.4 GHz frequency band

WiFi by the 802 numbers Never mind the alphabet, 802.11b was the first technology in this series to

reach the market The a specification came a bit later.

✦ 802.11b is the slowest of the modern standards but when it was first

introduced it was the least expensive and easiest to implement Systems

of this type transmit in the 2.4 GHz frequency band They are capable of moving as much as 11 Mbps of data

✦ 802.11a, the out-of-alphabetic order standard, transmits data within the

5 GHz band and can move up to 54 Mbps of data Although it is fast, the use of the higher-frequency band slightly reduces the overall range of devices because these signals are more likely to be absorbed or deflected

by walls or other solid objects between the transmitter and receiver

✦ 802.11g devices also transmit signals in the 2.4 GHz band, but they are

much faster than 802.11b WiFi equipment based on this specification can move as much as 54 Mbps of data Much of the gain is the result of using a more efficient coding technique (If you must know, 802.11g intro-duced orthogonal frequency-division multiplexing, a step up from com-plementary code keying I could explain the difference to you, but we’d both require a padded room before, during, and afterwards.)

✦ 802.11n isn’t yet an official standard, although that has not prevented a

number of manufacturers from offering devices that seem to fit the still-developing specification It’s a pretty safe bet that 802.11n, when final, will encompass the unofficial versions These devices operate at 5GHz and 2.4GHz, as needed, to deliver the best signal, and can deliver about

74 Mbps of data These devices also add multiple-input multiple-output

(MIMO) technology; it’s pronounced mee-moh by those in the know, and

Working a WiFi Network 530

it permits the use of multiple antennas at both the transmitter and receiver to improve performance As such it is less affected by certain types of interference, and antennas do not have to be “aimed” to deal with walls and corners See Figure 3-2

Each successive specification is downwardly compatible with previous designs,

which means that an 802.11n device also works with the earlier a, b, and g protocols

Avoid placing a wireless router in direct proximity to a 2.4 GHz cordless phone or a microwave oven In addition, if your home or office has both a 2.4 GHz router and telephone system, use the configuration panel on the router and any switches on the phone to assign them to widely separated channels

As an example, Belkin recommends setting its router at 11 and any phone at 1 You may need to experiment with various channel pairs to avoid interference, especially if you have neighbors with their own systems

In Table 3-1 I present a summary of three official WiFi specifications, along with two others that appear near to finalization and manufacture The 802.11y specification is expected to be administered in the United States under license by the Federal Communication Commission for use by com-mercial ISPs

Figure 3-2:

A Belkin WiFi router

in the unofficial

“Super G”

class that combines the 802.11g specification with MIMO antennas that can

be used independ-ently or together to improve the reach of the radio signal

Book VIII Chapter 3

Does Your Laptop Do WiFi? 531

Don’t expect the ranges listed here to necessarily match what you actually get; all sorts of things (walls, metal, interference, and even atmospheric con-ditions) can have an effect In other words, your mileage may differ

Protocol Release Radio Maximum Data Indoor Outdoor

(est.)

Does Your Laptop Do WiFi?

Here’s the easy part: Nearly all current laptops come equipped with built-in facilities for WiFi communication Models arriving in the stores as this book goes to press will most likely offer 802.11n; older machines may have come with 802.11g, 802.11b, or 802.11a

So, if your laptop has one of the latest standards built in, you’re all set — at least when it comes to the hardware side of the equation I discuss configur-ing your operatconfigur-ing system for wireless communication later in this chapter

But if your laptop doesn’t have built-in WiFi, if the included version is out-dated, or if the wireless hardware breaks, you have several good solutions:

✦ Install a WiFi adapter in a PC Card or Express Card slot If you go this

route, you’ll have to learn to take care not to damage the small nub of an antenna that extends from the end of the adapter; it is easy to break off and destroy the card or even damage the slot of the laptop It’s also important to turn off the power to the card when it is not in use You’ll also be dedicating one of a limited number of slots on your laptop to a single purpose

Attention passengers: Airlines prohibit the use of radio transmitters (including WiFi systems, cell phones, and remote control devices) while

in flight You need to turn off the power to your wireless system or remove it from a PC Card or ExpressCard to comply

Disabling the Original WiFi Adapter 532

✦ Replace the built-in adapter with a new unit certified by the original

equipment manufacturer If you replace the built-in hardware (only a

relatively few laptop manufacturers design their machines in a way that allows end users to get at the adapter without disassembling the entire case) you will have to carefully follow instructions mandated by the Federal Communications Commission (in the United States) or the equivalent in other countries; they do this to avoid the possibility of interference with other radio systems

✦ Add an external WiFi adapter that connects to your laptop through

the USB port You may have problems with this solution if your laptop

has USB 1.0 or 1.1 ports instead of the more advanced and speedier USB 2.0 design This solution has two designs:

• A simple device, about the size of a pack of gum, that plugs into the port and extends out to the side; the antenna is built into the case Again, the device presents a bit of a threat to the health of your machine because it sticks out a few inches; a glancing blow or a care-less return of the laptop to its carrying case with the adapter in place could damage it or the USB port

• A small external WiFi transceiver that attaches to the laptop with a USB cable Although this is an extra piece of hardware to drag around, it is much less likely to become damaged while in use

Disabling the Original WiFi Adapter

If your laptop has built-in WiFi but you add a new adapter that connects through the PC Card adapter or a USB port, you will need to remove or dis-able Windows drivers for the original unit You should also make sure that you turn off the switch for the built-in unit to save battery power and to avoid the possibility of interference

To disable the drivers, do this:

1.Go to the Windows Control Panel

2.Double-click System

The System Properties panel appears

3.Choose the Hardware tab

4.Choose Device Manager

5.Click that the + next to Network Adapters.

The hardware managed there appears in a list

6.Double-click the wireless component

Its properties are displayed

Book VIII Chapter 3

Building a Wireless Network 533

7.Click the Device Usage drop-down arrow

8.Select Do Not Use This Device (Disable)

This instructs Windows not to use the drivers associated with it

Building a Wireless Network

The process of putting together a wireless network is mostly a matter of configuring devices There are, by definition, no wires that need to be strung along the floor or through the walls; in many systems the only wires are a connection to a network router or a broadband modem, and a source

of power

✦ If you already have a wired network in place, all you may need to add is

a wireless access point This box connects at one end to an existing

Ethernet hub and terminates at the other end with an antenna that broadcasts and receives signals

✦ If you don’t have a wired network, or if you want to extend and expand

an existing one, the hardware you need is a wireless router This box

con-tains a port that connects to your broadband modem or to a port on an existing wired router and also includes its own router and Ethernet hub

as well as an antenna to send and receive WiFi signals

Depending on the design of your home or office, you may be able to install a single WiFi access point or wireless router and reach everywhere you want

to send the signal Or you may have to find a way to extend the reach of your wireless signal by bringing an Ethernet cable to another part of the structure and installing the wireless router there or by adding a WiFi range extender or repeater A repeater does exactly what its name suggests: it receives wireless signals (incoming or outgoing) and then rebroadcasts them in an amplified form

Setting up a WiFi router

The first wireless routers were built by and for highly technical users

The instructions were written for an audience of programmers and engineers and not necessarily in English There were switches to be set and in some cases there were requirements to modify the operating system

Happily, nearly all of that confusion is in the past Today many routers come with self-installation CDs or with telephone support desks that can quickly walk you through the process

If you want to get a sense of the task that lies ahead of you, visit the web site

of a router manufacturer before buying and reading the instruction manual

If you find insufficient assistance on the web site (or over the phone), I sug-gest buying a product from a different company