In the recently society, the cell phones were widely used, and the cell phone becomes the most important tool for daily life, while, the questions of mobile phones safety becomes more and more important.

Is mobile phone safe?

Nobody really knows the answer to this question and it has been the subject of fierce debate for many years. There is currently no scientific evidence to suggest that mobile phones pose a risk to health. However, since mobile phones are a relatively new technology that situation could change. There have been no studies into the long-term effects of using handsets not least because the technology hasn't been around long enough.

What are the possible risks?

There are fears that the electromagnetic radiation emitted from mobile phone handsets may harm health. In particular, there have been claims that it could affect the body's cells, brain or immune system and increase the risk of developing a range of diseases from cancer to Alzheimer's. While there is no evidence to back up these fears, laboratory tests on mice have shown that radiation from mobile phones can have an adverse effect on their overall health. It is still not clear whether those findings can be applied directly to humans.

A study by scientists in Finland, published in 2002, suggested that the electromagnetic radiation did affect human brain tissue. But they played down their findings saying more research was needed to see if the effects were the same in living people. Another study by scientists in Sweden, also published in 2002, claimed to have found a link between analogue mobile phone and brain tumors.

It suggested users of "first generation" phones had a 30% higher risk of developing tumors than people who did not. However, the findings were controversial and there have been no similar studies into the effects of modern GSM phones. There have also been reports of people suffering from headaches, fatigue and loss of concentration after using their mobile phones. However, these claims have not been scientifically substantiated.

What is the UK government's view?

The UK government commissioned a major study into the safety of mobile phones in the late 1990s. The Independent Expert Group on Mobile Phones published its report in 2000. The Stewart report, named after the group's chairman Sir William Stewart, concluded that there was no health risks associated with using mobile phones. However, it suggested that children should be especially careful about using mobile phone and recommended that they should only use handsets in emergencies.

The recommendation was based on the theory that children could be more at risk from the radio waves emitted by mobile phones. This is because their brains are still developing and their skulls are thinner, making it easier for the radio waves to penetrate them.

In 2002, the government and the mobile phone industry pledged £7.4m to a new research programme into the safety of mobile phones. Its 15 studies, being carried out by independent scientists, will aim to come up with definitive answers on mobile phone safety. The latest review of the evidence, carried out by UK government scientists, suggests mobile phones do not harm health.

However, members of the Advisory Group on Non-Ionising Radiation have warned that the situation could change if new evidence emerges.

What is the industry's view?

The mobile phone industry has spent millions of pounds investigating the safety of handsets. It is adamant that there is no link between the use of mobile phones and any adverse human health effects.

What steps can people take to reduce any risk?

Experts suggest that mobile phone users can take a number of precautions to reduce any possible health risks. Almost all agree that the best step is to keep mobile phone conversations short and to a minimum. Many believe that so-called hands free kits reduce the risks by cutting the amount of electromagnetic radiation entering the brain.

Do you know the reverse cell phones book? It can help you to contact with the long-lost old friend. If you have already known the function of the reverse cell phone book, you must eager to know how to find the reverse cell phone book. It can be searched on internet. You can try to search it on some major websites. 

But, it is unfortunate that a free cell phone directory that offers reverse look up service does not exist in real and you have to pay in order to find your near and dear ones. Though it's quite natural and there is nothing wrong in paying the website. This is so because cell phone numbers are not easily available and to collect so many numbers in its database, any website requires hard work. Thus, there is nothing wrong if you ask you a small amount. Also, the good part is that they charge you just once and you can conduct as many searches on the site as you want.

Also, if you are paying a reverse look up site you know that you are searching on a legal and legitimate website. Thus, you can be sure of not getting involved into any illegitimate tasks and can be sure that your number will be safe and would not be sold off to any telemarketer.

Beware of the websites that promise to help you find the number and details you are looking for free. Such sites can be unofficial in nature and can lead you to problems as well. Else, you will find that in the end they too ask you to pay a certain amount for conducting your search. Though still if you search hard on internet, you would come across certain free and safe sites. Here is a list of few free websites that may help you with reverse lookup process:

1. Nationalcellulardirectory.com: This is a free directory with a huge database and thus if you want to search for someone's number, first you have to add your number in their data base.

2. Cellphonedirectory.com: this website is getting popular day by day for offering free reverse search to its users. The best part about this site is that it's a volunteer site and you can remove or edit your list whenever you feel like.

3. Free-reverse-cell-phone-directory.com: Another example of a good and reliable free reverse cell phones book is this website.

We introduce the three websites for you to search the reverse cell phone book. To avoid cheating by some illegal websites and some website for charge, you can search though these three websites and you won¡¯t waste lots of time search around from the internet inefficiently.

Lots of people own a cell phone for those days, and they use the phone to connect with people all around the world, and the cell phones can do lots of things besides keep in touch with each other.

These days, cell phones provide an incredible array of functions, and new ones are being added at a breakneck pace. Depending on the cell-phone model, you can: store contact information; make task or to-do lists; keep track of appointments and set reminders; use the built-in calculator for simple math; send or receive e-mail; get information (news, entertainment, stock quotes) from the Internet; play games; watch TV; send text messages; integrate other devices such as PDAs, MP3 players and GPS receivers.

But have you ever wondered how a cell phone works? What makes it different from a regular phone? What do all those terms like PCS, GSM, CDMA and TDMA mean? In this article, we will discuss the technology behind cell phones so that you can see how amazing they really are. If you are thinking about buying a cell phone, be sure to check out How Buying a Cell Phone Works to learn what you should know before making a purchase.

To start with, one of the most interesting things about a cell phone is that it is actually a radio -- an extremely sophisticated radio, but a radio nonetheless. The telephone was invented by Alexander Graham Bell in 1876, and wireless communication can trace its roots to the invention of the radio by Nikolai Tesla in the 1880s (formally presented in 1894 by a young Italian named Guglielmo Marconi). It was only natural that these two great technologies would eventually be combined.

In these days, cell phones become so important that you can¡¯t leave it just for an hour. It will be more interesting when you are using the phone if you already know how the cell phone works.

Because the cell phones screen is exposed outside all day, it often scratched by the keys, coins and other items. Nobody want to have theirs stylish cell phone be scratched and make it look harsh. Follow the advice and keep your cell phone stylish.

1: Cut the microfiber cloth to approximately the size of a cell phone. It is best to cut several pieces so that you will have cloths that can be used later.

2: Combine 1 egg white with approximately 1 teaspoon of alum in a small saucepan. Mix the ingredients and heat them to about 150 degrees. Use a candy thermometer to check the temperature of the mixture. Do not remove the mixture from the heat until the egg white and alum have completely mixed.

3: Take one of the small pieces of microfiber cloth and immerse it in the mixture. Let it sit in the mixture for 1 minute so it can absorb as much of the mixture as possible.

4: Tear a sheet of aluminum foil and place the soaked cloth on top of it. Fold the foil around the cloth and put it in an oven heated to 300 degrees Fahrenheit. Leave the cloth in the oven until it is dry. Remove the cloth and rinse it under a cold tap for about 30 seconds.

5: Repeat steps 3 and 4 about three times. After the third time, let the cloth air out until it is completely dry. This could take up to 48 hours.

6: Rub the screen of your cell phones with the cloth. The mixture will decrease the appearance and the depth of the scratches on the cell phone. You now have removed cell phone screen scratches.

Follow the six steps and then, you need not to worry about that your cell phone screen could be scratched by sharp items, the scratch can be moved away, and the cell phone screen will keep slim and clear.

If you have a Nikon digital camera, you must want a flash to enhance your photos, when you get these two, do you know how to install the flash for your digital camera? Here are the instructions.

External flash units like the Nikon SB-800 provide you with more control over the output and angle of light. According to Nikon, the company can only guarantee the performance of this flash unit when you use it with a Nikon camera, and you could damage your SB-800 flash unit by trying to use it with another camera.

What about the instructions:

1: Prepare the flash unit. Using one of the types of batteries specified in your SB-800 flash unit user's manual, insert batteries into the battery chamber of the flash by following the guide marks on the unit. Replace the lid to the battery chamber. While the flash unit remains unattached to the camera, turn on the flash unit and test the flash and ensure that it fires. Turn the flash unit off, and do not turn on your camera yet.

2: Attach the camera flash unit to your camera. On the flash unit, you should see a lever near the mounting foot. Rotate the lever to the left and slide the flash unit's mounting foot into your camera's hot shoe, also called an accessory shoe. You can find the hot shoe on the top of your camera. Once you have done this, turn the same mounting lever to the right to lock the flash unit onto your camera. Locate a release button on the side of the flash head. Once pressed and held, this button will let you rotate the flash head into a forward position facing toward the subject of your photograph.

3: Set the ISO sensitivity. For some cameras, this will happen automatically. For others, you may need to change the ISO sensitivity using the Custom Settings mode on your flash unit. ISO sensitivity simply indicates the sensitivity to light of the image sensor. The greater the number is, the more sensitivity to light. Once you set the ISO sensitivity, adjust the zoom-head position or verify that it adjusted automatically. Adjusting this feature allows you to concentrate the camera flash light or spread it out.

4: Set the exposure mode and metering system for your camera. Nikon recommends setting the exposure mode to "Programmed Auto" and the metering system to "Matrix Metering" if possible. Then, set the flash mode on your SB-800 flash unit and set the camera's flash sync mode to "Front-curtain sync" for normal flash photography. At this point, you can now compose your photograph and shoot.

With the four steps, you can install the flash on the digital camera by yourself now, and you can experience the magic effect bring by the camera flash next.

Do you have a digital audio recorder? Have you experience the voice-activated recorders? Here is some knowledge of the digital voice-activated recorders about the understanding and the tips of it.

What Are Digital Voice-Activated Recorders?

Digital voice-activated recorders are a special subset of digital recorders that are designed to turn on when someone begins speaking. These recorders are great when you may be recording intermittent activity and don't want to waste a lot of space on your digital audio recorder; you'll only record the speaking, instead of all the dead space in between. However, one thing to look out for with voice-activated recorders is the lag time between the moment someone begins speaking and when the recorder activates. When you use a voice-activated recorder, it's not uncommon to lose the first word or the first several words of a sentence while the device powers up.

On the plus side, you won't have to wade through a lot of silence to get to the part of the recording you want. These recorders are also stingier with memory and battery life, so you'll get more useful hours of recording.

Great for Dictation, Interviews and Lectures

Voice-activated recorders shine when you're taking dictation, attending lectures or conducting interviews. Voice-activated dictation is popular in a number of professions, including general corporate settings and legal proceedings such as depositions and court appearances. You can use voice-activated recorders when you're conducting a series of interviews or attending lectures because you don't have to worry about dead space between speakers; you'll only record when people are talking. You can simply set up voice activated recorders and let them run, even leaving the room if you need to because you know the recorder is running.

Who Makes the Best Voice-Activated Recorders?

The most popular voice-activated recorders are the Olympus VN-4100PC and the Sony ICDUX80. The Olympus VN-4100PC is the most popular voice-activated recorder, costing around $50 with 256MB of internal memory and solid sound quality for recordings. The Sony ICDUX80 is a popular high-end voice-activated recorder, priced at around $150 with 2GB of internal storage and MP3 playback capabilities. Both of these recorders are appropriate for dictation, recording lectures, interviews and office meetings. These digital voice-activated recorders connect to your computer via USB, allowing you to easily download, organize and store your files. The higher quality of the Sony makes it a good choice for interviews that you want to post online or for corporate settings where people are talking at a normal volume and greater sensitivity from the recorder is needed.

Don't Record Phone Calls

One popular application for voice-activated recorders is to record phone conversations. However, be aware that unless you inform the party that you are recording, you could be engaging in an illegal activity. Recording a phone conversation without the consent of both parties is illegal in 12 states, while the other 38 states require at least one party's consent to record phone calls. If you are looking at voice-activated recorders to record phone calls, check your state laws to ensure you're not breaking the law. Some voice-activated recorders come with attachments that plug directly into the phone line for easy recording. The quality of these recordings is much higher, so it's worth looking for this feature if you'll be recording phone calls.

The digital voice activated recorders is the most interesting kind of digital voice recorders. You can use it to record your class and lecture and you can also make some fun with it besides study. It will be more fun than an ordinary digital voice recorder.

How to choose a flash unit for your digital camera? To choose the digital camera flash, you should consider the following advices.

The built-in flash on a digital camera rarely provides enough light or enough versatility for the dedicated digital photographer. For this reason, many digital photographers choose to use a flash unit for their digital camera. Flash units come in many shapes and sizes, and must precisely match the digital camera.

What about the instructions:

1: Check to see whether your digital camera has a "hot shoe." A hot shoe is a jack on your digital camera that connects your camera with an external flash unit. If it does have a hot shoe, you will find it easier to choose a flash unit for your digital camera. Newer digital cameras may even have a wireless hot shoe, which you can use with a wireless flash unit.

2: Identify flash units that are compatible with your camera. Choose the one that most suits your needs and budget.

3: Read the manual included with your flash unit to learn how to connect the unit to your digital camera.

4: Connect the flash unit to your digital camera and take pictures.

Tips & Warnings

Digital cameras are extremely susceptible to red-eye. Choosing a flash unit with a tilting head can eliminate some of this. Simply aim the flash toward the ceiling and bounce the light back toward your subject. Bouncing also eliminates strong shadows or lights in your pictures.Due to changes in design and voltage, an old or incompatible flash unit can damage your digital camera. When you choose a flash unit for a digital camera, make certain it is compatible with your camera.

With the guide of using the digital camera flash and the tips and warnings of choosing the digital camera flash, you can have a great experience of shooting with the digital camera flash.

A digital voice recorder can do much things for you, it can record lots of notes that you can not remember by yourself and you don¡¯t like to write them down. It can be convenient to use a digital voice recorder. Then, how to choose the digital voice recorder that is right for you?

1. Consider how much recording time you need. Newer models are always coming out that have more and more recording time available on them, so even if you plan on using your recorder constantly you should be able to find one that suits your needs. Some can hold well over 100 hours of audio. You can find used, cheaper models that hold much less. One thing to remember, though, is that many recorders allow you to record at different levels of quality. The advertised maximum recording time advertised is typically only available at the lowest quality setting, which might not suit your needs. For example, my Olympus VN-240PC will record up to four hours (hence the "240" -- 60 minutes times four equals 240). My recorder's four-hour capability becomes one hour and 28 minutes on the highest quality setting.

2. Picking a microphone is almost as important as picking a recorder. Of course, recorders come with their own built-in microphones. That's how they record, obviously. And the built-in microphones are fine if you're only going to record while holding the recorder up near your mouth. But if you plan on giving a speech and recording it, or recording someone else's presentation, or recording people more than a short distance away in a room, you should get an external microphone. Fortunately, there are a number of inexpensive models. There are three kinds in particular you should consider. The first is a lapel or tie-clip microphone. This is perfect if you're giving a speech and want to record yourself. The second type is called a unidirectional microphone. This records sound coming from the direction you point the microphone in, which is good if you want to record one person talking when you're sitting around other people and don't want their chatter interfering. The third kind is called an omnidirectional microphone. This records sound coming from all around it, which is good if you do want to pick up audience chatter (perhaps to hear the audience's reaction to certain comments).

3. The third thing to consider is whether you need a recorder that can back up its files to a computer. If you do, you'll have to pay a little more, but it can be worth it. You can copy a recording to your computer and immediately erase it, freeing up more space on your recorder. Otherwise, you'll have to keep the recording until you're completely done with it. Of course, if you have 100 or more hours available, that might not be a problem.

Those are what you want to consider if you want to purchase the digital voice recorders, what¡¯s more, you should by some accessories, for example, the headphones for your digital voice recorder.

Learn some things of your digital camera, you will get some knowledge of it and make effect use of the digital camera. Here are also some tips warnings on your digital camera besides the method of how to use the Cnon 420EX.

The Canon Speedlite 420EX is an auto zoom external hot-shoe mounted flash unit designed for Canon EOS digital cameras. The unit attaches to the top of the camera, creating a much stronger light source than the on-camera flash, and is easily detachable when not in use. Using an external flash unit illuminates the subject of your photograph without the harsh, unnatural light of in-camera flashes. An external flash like the Canon 420EX also reduces redeye, is more powerful than the in-camera flash and allows the photographer full control over lighting the subject.

1: Install four AA batteries in the battery chamber.

2: Speedlite 420EX on the camera by loosening the locking collar on the bottom of the flash unit, sliding the unit's mounting foot completely on to the camera's hot shoe and tightening the locking collar.

3: Choose your wireless setting. For normal flash operation, set the wireless selector to "off." For wireless flash operation, set the wireless selector to "slave."

4: Turn on the power by setting the main switch to "on." The flash is ready for use when the "pilot" light is lit. The energy saving mode will automatically take effect after 90 seconds of idleness.

5: Adjust the flash head according to where you want the light directed. By directing the flash upwards toward the ceiling you will softly illuminate the subject and its immediate surroundings. Directing the flash straight at the subject will result in a stronger illumination on the subject and little of the background.

6: Compose your shot and take the picture. Your 420EX should automatically fire. The flash exposure confirmation light on the back of the flash will light for three seconds to signal the correct exposure has taken place.

Tips and Warnings

You may want to invest in rechargeable batteries and a wall charger as buying new batteries can become expensive. In a good charger, batteries should be ready for use in two hours. If your flash exposure confirmation light is not lit, your photo may be underexposed. Move closer to your subject or readjust the flash head. Wait until the "pilot" light is lit before taking your next shot. The flash will not fire until the "pilot" light is on. Placing a diffuser like the Omni-Bounce over the flash head helps give more even light coverage across the frame. Remember to loosen the locking collar before removing the flash unit from the camera. Failure to do so can result in a bent hot shoe and broken mounting unit., remember the light will be tinted the same color as that surface when bouncing light off a hard surface. White walls work best. Bouncing light off a red wall will result in a photo with a red tint, a blue wall will give a cold blue tint, etc.

If you own a Canon 420EX or you are going to purchase one, and not very familiar with it, the article can help you get some knowledge of the features of your Canon 420EX and the way to use your camera.

Three new digital voice recorders were announced by Olympus. In this article, we will talk about the details of these three model digital voice recorders and share the information with you.

Olympus Rolls out DS Series digital voice recorder. The New models replace the popular DS-2200 and DM-20 recorders. With new recording mode ¡°STXQ¡±, Stereo or two channel recording the DS series is geared towards several recording environments including interview, conference, and lecturer.

The new models record brilliantly in scenarios that are difficult to capture clear audio such as noisy environments and large areas with multiple speakers. Perfect for meetings, depositions, court room hearings, and class room lecturers. The DS50, DS40, & DS30 offer two Filter options, Low Cut Filter and Noise Canceling. The Low Cut Filter helps cut Low Frequency sound such as Air conditioner or Projector noise. So, playback sound is natural. The Noise Canceling feature makes sure noisy sound is removed to make sound more clear. This function work¡¯s in playback mode and, this technology work¡¯s in stereo mode (s) as well.

Key Features

The highest sound quality in the Olympus line-up with the new XSHQ Remarkable Stereo Sound Quality mode. The new DS-Series devices can record and play audio content up to 44.1 kilohertz (kHz), which is equal to the sound quality of most CDs. Removable stereo microphone for recording high-quality digital audio.

Voice Confirmation and Instruction Manual "Voice Guidance" function that talks, confirming which settings have been selected and helping visually challenged users to navigate the device.

Music Recording and Playback Both MP3 and WMA (Windows Media Audio) files can be downloaded and played back on the device.

Long Lasting Power: 32 hours of continuous operation

Software

Olympus uses WMA (Windows Media Audio) recording format. Since it is a standard file format, it is easier to work with and share the files with others. The files can be played and/or burned to a CD using Windows Media Player. The Software included with the devices allow for easy downloading of podcasts and the podcasts' contents are updated automatically each time the digital voice recorder is connected to the computer. 

Overall Conclusion

Olympus excels at designing recorders to fit specific market segments. Their dictation recorder product line up which includes the DS-4000, DS-3300 & DS-2300 are the preferred devices for professional dictation and transcription. With the same attention to design and functionality, the DS-50, DS-40 and DS-30 will most likely make Olympus the front runner in the interview, lecturer, and conference market as well.

After we share about the information about the three new model digital voice recorders, you may get some interesting on these digital voice recorders, you can try on one of these, you will find that it will not be disappointing.