Buying a Cellphone
Back in the real world, choosing a cellphone can be a complicated decision. Beware of slick salespeople offering "free" phones, often with bundled accessories and other freebies, such as televisions or computers. They require you to sign a service contract that lasts at least a year and can be difficult to get out of after that. The companies make up more than the cost of the phone in monthly service charges, and most people end up paying hundreds of dollars.
This isn't to say that all the cheap or free phones are necessarily a bad thing; it's standard practice in many countries for the operators to subsidize the cost of phones, and sometimes the service contracts offered are good value. But it is important to shop around. "Prepay" deals with no contract attached may be better if you need a phone only for emergency use, while if you want Internet access, it may be worth turning down the free phone in favor of a more advanced model.
Each mobile operator typically offers many rate schedules and payment plans, seemingly designed to confuse. In general, paying a high monthly line rental leads to reduced per-minute charges. But even for the same monthly fee, there are usually choices such as how much to pay for different kinds of calls, and whether international roaming is allowed. Pick the wrong one and you could end up paying far too much, or you may even find that your phone doesn't work when you most need it.
Posers
Companies like Nokia freely admit that many of their phones are sold on appearance, not features. They target specific models at groups they call "posers" and "yuppies." A case in a fashionable color will often prove more popular than Internet access or long battery life, and visual appearance is expected to become more important as the diversity among users widens. The same applies to other mobile devices; the most sought-after Palm PDAs tend to be those with the most stylish case, not the most technically advanced.
The trend toward stylishness will continue as computers move from functional devices to consumer products, but phones won't become less functional. Most manufacturers plan to build some kind of wireless Internet capability into all its mobile phones, along with basic computer functions. There is already a wide choice of phones and other devices based on WAP and similar standards, with better services that approach the quality of the wired Web on the way.
If you want the mobile Internet now, your choices depend mainly on where you live. In Europe, WAP is becoming ubiquitous. Most analysts agree that it is more of a gimmick than a true wireless Internet service, but it could still be worthwhile; the messaging services, originally intended just to test the capability of GSM phones, are hugely popular. Japan has a rival system, which is closer to the real Web, and the U.S. has different services in different areas.
Globalization
Movies like to show the hero using a cellphone aboard a jumbo jet or underneath the desert in Iraq. Both these scenarios will remain fiction for many years; it's still impossible to get a cellphone that will work everywhere in the continental U.S., let alone the world. Only satellite systems achieve true global coverage, and they work only outside.
For world travelers, the best choice is probably GSM, but this is actually available in four different varieties. There are two versions of the American D-AMPS (Digital AMPS) system, and two of cdmaOne, the advanced cellular technology designed by Qualcomm. Many phones support more than one version of a system, or even different systems, but it's important to make sure that the one you choose will work where you want to take it. In particular, American GSM uses different frequencies than European GSM.
Radio Active
Wireless is hot, but some would say too hot. Mobile phones use exactly the same type of radiation as a microwave oven and can have the same effects. Many people are concerned about the health risks of holding a microwave source so close to their heads, and the wireless Web means that the problem is set to get much worse. Higher data rates mean higher power transmissions and more radiation. Prototypes of next-generation phones got so hot that they burst into flames.
Plenty of small-scale studies have been carried out, with results ranging from claims that phones are entirely safe to claims that they cause cancer in rats. The most accurate are probably studies using human volunteers and real phones, which found a small improvement in reaction times of people who had just been using a mobile phone. A story about cancer in rats scared many people; it showed that the rats suffered DNA damage after continuous exposure to microwaves for eighteen months. However, most mobile phone users do not use them for this much time, and the dose relative to body weight is far lower for a human.
The scientific consensus is that the radiation from mobile phones is harmful, but that the dosage is so low that most people will suffer no ill effects. There are already safety guidelines issued by various international bodies, shown in Table 1.1. These limit the SAR (Specific Absorption Rate), which is the power allowed per kilogram of body tissue. A British government report in 2000 recommended that children under 16 be discouraged from using mobile phones altogether, as their brains are still developing.
Shields are usually a waste of money unless you live directly underneath a base station; they do block the radiation, but also weaken the signal. The opinion on hands-free headsets is more mixed. Most experiments have found that they keep radiation away from the head, as common sense suggests. However, one study carried out by the British Consumers' Association suggests the opposite. It claims that the wires leading to headsets act as a wave-guide, channeling radiation directly to the brain.
One possible explanation for the conflicting results is that the increased radiation shown in the British Consumers' Association's study was caused by keeping the wire too close to the phone's antenna, which can induce currents. This means that a well-designed headset should be safe, if users don't mind appearing to talk to themselves. A better option is to sever the link between the phone and headset entirely by using a very low-power wireless technology, such as Bluetooth.
Most of the studies so far relate only to short-term effects. The greatest fear is that radiation will cause brain cancer, something that might become apparent only after many years. Mobile phones are so new that their long-term effects are still unknown and could remain that way for a generation.
Some scientists say that research into mobile phones is now at the same state as research into smoking was in 1950: There are fears, but no hard evidence. However, similar fears have existed about technologies later shown to be harmless; many people were afraid to allow electricity into their homes in 1900, and some scientists back then agreed with their fears. It could be decades before we know which comparison is most accurate.
normal: Web Resourceshttp://www.s3.kth.se/radio/4GW/ The Personal Computing and Communication research group at Sweden's Royal Institute of Technology istrying to develop a fourth-generation mobile system for the year 2010 onward. British Telecom's scientists explain why they believe that wireless technology will eventually enable everyone to live forever. The Independent Experts Group on Mobile Phones is a committee set up by the British government to produce safety guidelines about cellphone use. |