What is?

CDMA stands for Code Division Multiple Access. It is a technique used for digital communication, and wireless technology in particular, that involves multiplexing. Whereas conventional communication systems use constant frequencies, CDMA uses multiple access, or multiplexing. Multiplexing, in this case accomplished through the specific type known as spread spectrum, uses varied frequencies to transmit audio signals. This, coupled with code division which requires a certain code to send and receive the frequency, further protects CDMA communications from interference.

Radio systems, one of the earliest forms of telecommunication, required users to have distinct frequencies. Two earlier forms of wireless communication illustrated the limits of methods previous to CDMA. Frequency Division Multiple Access or FDMA only allowed users to operate on a single frequency. For instance, when tuning in to a radio to get sound, a listener must select one frequency or the other. The listener must also tune the frequency to filter out noise in the spectrum that is not associated with one frequency or the other.

The other form of early radio communication was Time Division Multiple Access or TDMA. In this case, users could not share a frequency and each user had to coordinate his or her turn on that frequency in order to communicate. Both FDMA and TDMA posed restrictions for early users, particularly the military. As early as World War II, the military needed to communicate across vast distances that required wireless technology. That was also the case for their adversaries. Military communication units did not have time to wait their turn to transmit sound, or to find a frequency.

Previous telecommunication systems allowed military communication units to transmit sound into the same spectrum their adversaries used. The military’s signals needed a unique identification through a distinct code to avoid interference from enemy communication. The receiver of that message on the other end could similarly retrieve the message based on its unique code in the spectrum.

Just as the radio moved from military use to commercial use, so too was the case with the wireless technology. CDMA became the early choice for personal communication because it could allow multiple users to communicate within the spectrum, avoiding interference or blocking among users. In 1999, CDMA became the standard technology for the telecommunications industry for its growing wireless systems. Since there are large numbers of users in the system communicating at the same time, code division ensures that each user’s signal remains separate in the spectrum.

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The iTunes program is a downloadable media player available from computer giant Apple, Inc. In addition to being able to play media files such as music and movies, the application also connects to the iTunes store, an enormous resource for free and purchasable digital media. Since its release in 2001, iTunes has become a near standard application for most computer users, and has greatly fueled the digital media revolution.

The original model for the program was not developed by Apple, Inc. Instead, the initial application was created as a music player called SoundJam MP, distributed by software publisher Casady & Greene in 1999. Apple, Inc acquired the rights to the program and began adapting the user interface and adding CD-burning capabilities. In January, 2001, the first version of the program was released to near instant success. Since then, the company has released several updated versions, and continues to improve the abilities and functions of the program with each new release.

Apple, Inc made the program a necessary application for use with their unbelievably popular portable music player, the iPod. In order to manage media files, add new content or edit content, the iPod must work with iTunes. However, recent versions of the program make it compatible with other MP3 players, though in the opinion of many experts, it continues to work best with other Apple products.

Interestingly, the program was released many months before the first iPods, and nearly years before the attached online music store became available. At first, the program acted simply as an organizational application for arranging music stored on your computer and burning CDs. Music could also be easily uploaded onto the computer through the program, and stored in an easily accessible library. Until the release of the iPod, the opening of the iTunes store, and more recently the addition of video downloading, the potential of the program was hardly understood.

In the 4.3 version of the program, released in 2005, video capabilities were added. Shortly afterward, through the iTunes store, movies, video podcasts and television programs were now available to download and play on the computer or on video-capable portable players. This function added completely new levels to the program, and helped increase its already impressive popularity.

The invention and promotion of portable digital media has revolutionized both the music and computer industry. In many ways, iTunes is as groundbreaking as the invention of video tapes or CDs. As a reaction to the copyright debacle following the widespread use of file-sharing programs such as Napster, Apple’s music program has allowed the legal and safe distribution of media over the internet. Online stores still remain in their infancy, only a few years after the wide availability of the internet, but iTunes is clearly an example of the inherent commercial possibilities of the World Wide Web.

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A dial tone is the signal you hear on a telephone before you dial a phone number. In most instances, the signal disappears after you dial the first number.

The dial tone was widely established as telephone systems became automated, starting around 1947. Prior to that, a person had to talk with a switchboard operator in order to connect with another party. When the operator was no longer necessary, many people assumed their phone wasn’t working because they heard no sound on the line. The dial tone was created so the caller knew the phone was indeed connected and working before making the call.

At home or in an office, several phones can share the same telephone line. The use of the dial tone also eliminates confusion if one party picks up the phone and the line is being used elsewhere.

The early dial tone resembled a buzzing sound and was created by a motor driven machine. Today, the sound of the dial tone in North America is that of two interfering frequencies of 350 and 440 Hz (Hertz). These signals correspond to the concert pitches of “A” and “F” respectively. Most of Europe uses a single dial tone of 425 Hz.

The dial tone has also been adapted to let the telephone user know of voicemail or other calling features. This is done via a stuttered dial tone when the phone is picked up.

In general, cell phones do not use a dial tone. If the phone is off, then the user knows it is not in use since there is only one “line” per phone. The number can be dialed ahead of time, and the “send” button replaces the dial tone. A recent incarnation of the cell phone, however, designed for older generations, uses a dial tone when the phone is opened.

Other common telephone tones include the disconnect tone that the telephone makes when the other party hangs up, the busy signal, and the loud tone that the phone makes when the receiver is off the hook. There are also several special information tones. These are the three-beep tones used by the phone company prior to the recorded messages that explain why the call did not go through.

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Brown’s gas is a chemical used in high-powered lights and lamps, torches, and welding tools. Also known as oxyhydrogen, Brown’s gas was named for Yull Brown, a Bulgarian inventor who first patented two producers of oxyhydrogen. It is a technology that burns water as fuel, and can be used for heating, cutting, fusing, and is popular in automotive industries. It is also known as HHO gas, di-hydroxy, green glass, water glass, and knallgas.

Brown’s gas has been used to produce oxyhydrogen lamps, like the limelight sometimes used in stage lighting. It is also used in the melting of and working with many metals. Because of the high temperature possible in oxyhydrogen, the chemical has been used to melt various metals, such as platinum, since its discovery, though more efficient and safe methods have since been discovered. The oxyhydrogen torch has been used in this method for cutting glass and thermoplastocs as well. It has also been used as an experimental automotive fuel.

Brown’s gas is a mixture of the elements of water in the same proportions as water: hydrogen and oxygen mixed at a 2:1 ration. An electric current is used to separate and disassociate the molecules of the water, allowing the hydrogen and oxygen to act independently of each other. It can burn with almost any volume of hydrogen, and when burnt it converts to water vapor and releases energy. This energy released is enough to keep the reaction burning, and the chemical powered, as long as hydrogen remains.

Brown’s gas burns at a rate of 241.8 kilojoules of energy. It can reach a temperature of 2800° Celsius (5072° Fahrenheit) , which is nearly 700° C (1290° F) hotter than a normal hydrogen flame produced in air. When the molecules are in their proper ratio and producing their own energy, ignition is enough to keep the gas burning and can reach a level 3.8 times higher than that of a normal oxygen flame.

Yull Brown first patented an electrolyzer in 1977 to utilize the power and benefits of Brown’s gas. The electrolyzer is a tool that separates the oxygen and hydrogen of water by decomposing it into its separate components. Brown’s gas has been introduced to manufacturers and the general public through generators which prepare the gas for welding. It is a relatively safe substance to work with. It is odorless and not poisonous when inhaled or ingested, and its cheap cost and abdundance, only the price of electricity and water, make Brown’s gas an available and convenient chemical for many scientific endeavors.

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Digi-necking is rubbernecking for the digital age; instead of just slowing down to look at an accident, rubberneckers today can photograph it with a digital camera, cellphone, or another device, thereby having a memory to take along with them. Just like rubbernecking, digi-necking can be very dangerous, and it is also considered rude in some regions of the world. Traffic engineers in particular are concerned with this evolution in the time-honored practice of rubbernecking, because it can lead to problems with the flow of traffic around an accident.

Rubbernecking, of course, is a phenomenon in which passersby and bystanders gawk at the scene of an accident. For first responders, rubbernecking can be potentially dangerous and irritating, because it interferes with their ability to handle and secure the scene. Rubbernecking can also lead to accidents, because a rubbernecker might be so distracted by a gory scene that he or she doesn’t notice the car in front has stopped, slowed, or changed position in the road.

When people engage in digi-necking, they whip out a camera to photograph the scene of the accident. While the desire to photograph the scene out of morbid interest might be desirable, the time it takes to set up the frame and take photographs can make digi-necking more dangerous than rubbernecking, and it can also slow the flow of traffic around the accident.

One could argue that digi-necking could potentially be useful, because the photographs could be used by battling insurance companies. However, when first responders arrive on scene, police officers often arrive as well, and they take extensive photographs to document the scene; these photographs are far more likely to be useful than snapshots taken by people who don’t know how to photograph accident scenes well. For the victims of an accident, digi-necking can also be offensive or embarrassing, especially if the photographs later end up on the Internet.

Several studies carried out by traffic engineers and psychologists have shown that stopping to rubberneck can be dangerous. Lingering at the scene of an accident can slow the response time of the brain to external stimuli, which can pose a threat if conditions on the road change suddenly, and it also interferes with the goal of clearing the road as quickly as possible so that it can return to normal function. The best thing to do when one approaches an accident is to slow down and follow the directions of emergency services personnel, not to embark on a career as an amateur accident photographer.

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A Neo-Luddite is someone who believes that the use of technology has serious ethical, moral, and social ramifications. Operating under this belief, Neo-Luddites are cautious to promote early adoption of technology, and while they are not necessarily opposed to technology, they would prefer to see a more serious discussion of the role of technology in society. Some Neo-Luddites actually dislike technology, opting for a life of “voluntary simplicity,” but this is not always the case.

The term “Luddite” comes from a political movement during the Industrial Revolution. The Luddites disliked the spread of mechanical devices such as mechanized looms to accomplish tasks which were formerly performed by people. They held marches, destroyed factories, and engaged in other types of activism in an attempt to prevent further technological development. Ultimately, the Luddites were unsuccessful, but when people started to question technology in large numbers again in the 1970s, they revived the concept, calling themselves the “New Luddites,” and the Neo-Luddite movement was born.

As a general rule, people who have questions about the use of technology do not use the term today. Instead, it is used in a deprecating way by advocates of technology, to suggest that the thinking of Neo-Luddites is outdated and outmoded. The fantastic failure of the original Luddite movement is sometimes cited as an argument that opposition to technology is ultimately fruitless.

The Neo-Luddite position is that rather than assuming that technology is always neutral or even beneficial, people should think about the ramifications of technology. For example, advanced life support systems now allow people to live much longer than was possible in previous eras, but these lives are not always fulfilling or happy. Technology is also used in a variety of ways which could be perceived as harmful; for example, several cities use extensive surveillance systems to keep an eye on the populace, which many people see as a breach of privacy.

Most people would not argue with the Neo-Luddite idea that technology is changing human society, and sometimes even shifting what it means to be human. Stopping to think about the effect of technology on society is the main goal of many Neo-Luddites, some of whom freely admit that some technology can be very beneficial. As often happens with small movements which are critical of a larger social trend, the voices of Neo-Luddites are often overwhelmed by a fringe minority, making it hard for the voice of reason to be heard. Fans of technology criticize the Neo-Luddite position, arguing that the benefits of advances in technology far outweigh the potential problems and risks.

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Whisper mode is a cellular phone setting available on many phones and headsets produced by Samsung Mobile. By amplifying the power of the phone’s microphone, it allows the speaker to talk more quietly, while still being heard and understood by the person on the receiving end of the call. Whisper mode can be useful in relaying private or confidential information, but can still cause a serious breech of etiquette when used in inappropriate ways.

Many people have had the unpleasant experience of having to listen to the shouted cell phone conversation of a person nearby. While it can be an interesting source of gossip, it can also be a serious imposition on anyone close enough to listen. The quieting ability of this mode is meant to reduce the volume at which you speak, allowing you to talk in a normal or quiet tone regardless of the nearby noise level.

If you are in a loud or crowded environment and on your cell phone, it can be useful for the other person to have whisper capabilities on their phone. By increasing the sensitivity of their microphone, they will be more audible to you despite whatever audio distractions are occurring. It can also eliminate the need for you to shout into the phone in order to be heard over the noise around you. Be sure to avoid raising your voice if you have whisper mode turned on, as you will be extremely loud to the person on the other end of the call.

Whisper mode can be useful if you are relaying confidential information by telephone. Many automated systems reached by phone now require you to give personal information to access accounts or services, such as your social security number, birth date, full name, or password. By using whisper mode, you may be able to protect your information from anyone near by. In an age of extreme vulnerability to identity theft, this can truly help save your information from getting out to thieves.

While whisper mode is meant to increase phone etiquette, it can actually have a reverse effect. Many atmospheric areas, such as movie theaters, restaurants or museums, have strict rules forbidding the use of cell phones. Some people may interpret whisper mode as a way to get around these rules, since you will be speaking quietly. This is a serious breech of politeness, and may not buy you the privacy you are seeking. In quiet locations, whispered conversation is still likely to be overheard, and in fact may make people unconsciously more inclined to try to hear what you are saying.

Whisper mode comes as a standard feature on many Samsung Mobile phones. It is usually reachable through the menu, and can often be activated from the tools section of your cell phone. Samsung brand phones are available through most major cell phone carriers, including T-Mobile, Verizon and Metro PCS. If you are interested in getting a phone with whisper technology, be sure to check with your carrier to see which models include the feature as a standard.

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Iridium flares are nothing more than the sun’s reflection off the communications satellites owned by the Iridium Satellite company and used for satellite phone service. The antennas of these satellites are positioned in such a way that they can brilliantly reflect the sunlight, producing a brief spectacle in the night sky, known as a glint. Sometimes, the flare is so bright, it can even be seen during the day.

The antennas that produce the iridium flares seen from the ground are not what many may imagine when they hear the word. Rather than being made from iridium, a metal similar to platinum and used for its harness, the antennas on these satellites are plates of highly reflective aluminum. Each satellite has three antennas with a height of 6.2 feet (188 cm) and a width of 2.5 feet (86 cm).

Iridium flares are different from the normal occurrence of seeing a satellite cross the night sky. In darker areas, seeing satellites is a commonplace event. Stargazers can readily point these out to newcomers as they see them move steadily from one side of the horizon to the other, sometimes fading in and out of view.

Instead of these typical occurrences, Iridium flares are a brilliant flash of light as the satellite’s antenna catches the sun at just the right moment. They usually only last a few seconds, so unless stargazers are actually looking for them, they can be quite easy to miss. However, with some 66 active Iridium satellites in orbit, there are plenty of opportunities.

It is hard to say for certain when the first glint was spotted, but photographs of the flares date back to 1997. At the time, the flares were considered unpredictable. Those wishing to see them now, however, have an advantage. Astronomers can predict when and where they will take place and websites detailing this information have been created. In addition to predicting when Iridium flares will pass within your view of the horizon, these websites can also predict other passings of satellites, the space shuttle and the International Space Station.

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A touch screen allows user commands to be issued by pressing corresponding buttons on the screen. Since their introduction in the 1970s, touch screens have become popular for computer and media technology. Chances are, if you have used an automated teller machine (ATM), owned a personal digital assistant (PDA), or played with the newer cell phones, you have already used touch screen technology.

There are several commonly used systems that allow for touch screens to work. Each method allows for commands to be translated by the computer as a result of touching a certain point on the screen. Many convert the coordinates of the touch locations to specific actions to be taken by the system.

One of the most common systems for touch screens is called resistive. Covering the transparent panel of the screen are conductive and resistive metallic layers that have an electric current between them. When the screen is touched, the electrical current can tell the exact spot of contact and send the coordinates to the operating system. This is similar to how a mouse works with a computer, where the central operating system notes the exact point of a click and can respond by activating the action requested.

Capacitive systems give a brighter and clearer image than resistive technology, as the electric layer on the monitor allows more light to pass through. These touch screens carry an electrical charge that reacts to the electrical fields of the human body. Circuits at each corner of the screen measure the distortion that occurs when you touch the screen and cause the operating system to react.

Strain gauge touch screens are often to be found on public ATMs. By using a spring mechanism in the corners of the screen, the strain gauge can measure the pressure put on a touch point. As anyone who as ever used an old ATM can tell you, the pressure points can wear out with use, preventing the machine from responding correctly.

Touch screens are considered useful in that they eliminate excess hardware such as computer mice and keyboards. Some experts believe that the day is not far off when personal computers will consist solely of a monitor and central processing unit. With the trend of making portable devices lighter and more compact, touch screen technology may also soon be as common for laptop computers as it already is for small mobile devices like cellular phones.

It can take considerable pressure to activate a touch screen, resulting in strain on the fingers and hands if used consistently. Some PDAs and smartphones include a thin instrument called a pen or stylus, which not only reduces strain but also allows greater precision. As touch screen technology becomes more prevalent for mobile devices, a stylus can be used to type on full touch screen keyboards and play mobile video games.

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A battering ram is a type of siege engine used to break down walls or doors. Popular in ancient battles and medieval castle warfare, modern forms of the battering ram are still used today. Made from the trunks of enormous trees, battering rams were once the height of siege technology, and were incredibly difficult to stop once attackers reached the gates.

The simplest form of a battering ram is simply a large, relatively straight tree trunk. Any branches would be shaved off before using the ram in battle, and trees such as oaks or large firs were preferred for their strength. Many men would carry the ram by hand, propelling it into its target using their own strength. Some pre-prepared rams were capped with metal, to strengthen the impact and prevent the ram from shattering or breaking.

One of the problems with the early battering rams was that it could take a long time to bash a sturdy gate down. Aside from the strength of the men carrying it giving out, the long battering period gave defenders quite a while to shoot the men with the ram or pour boiling pitch onto their heads. It became clear that a more mobile form of ram was needed that would pack additional power and prevent the attackers from having to stand directly under the walls as they used it.

Originally, armies added power to the ram by placing it in a sling, which could be swung back and forth, giving the ram greater momentum. To aid in carrying it, the sling and ram were placed on a wheeled wagon. The sling, while handy, didn’t provide additional protection for the wielders of the battering ram, so eventually a covered shed was added above the ram, where attackers could hide as they worked the ram. This construct came to be called the turtle or tortoise, as the log would swing out when the carriage was moved, like a turtles head emerging from its shell.

Defenders often responded by using flaming arrows to set the sheds on fires and installing moats and drawbridges around the castle to prevent the battering ram from ever reaching the door. Some defenders would also try to pad the door from the outside to diminish the impact of the ram. This strategy was rarely successful, however, as shoving mattresses down in front of the gate would not have much affect on the blow given by an enormous oak tree.

Battering rams have been possible throughout history as a siege weapon. Artifacts from ancient cultures show that ram technology has been used since at least 900 BCE. After the castle era ended, they fell out of use somewhat, but the basic principle of the battering ram remained an important piece of warfare knowledge. Today, modern rams are often mounted on military vehicles used for forced entry, providing considerable increase in impact while protecting the passengers inside the car.

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