Should Cell Phone Jamming be Legal?

Jamming a cell phone is illegal in the U.S. Very illegal. And not just by ordinary citizens. It's illegal for theater and restaurant owners to jam (block) calls, and even state and local police or prison officials. The U.S., in fact, has the strictest laws in the world against jamming cell calls.

U.S. law prohibits not only buying, selling, carrying or owning a cell phone jammer, but also posting a Craigslist ad that claims you're selling one. If you're caught with a jammer, you could face up to $11,000 in fines and up to one year in prison.

The ban against cell phone jammers isn't new. In fact, it's the musty old 1934 Communications Act that bans the jamming of any commercial radio communication, a law that predates not only jammers but cell phones themselves.

Cell phone jammer laws vary throughout the world. In the U.K. and Japan, for example, anyone can own a jammer -- as long as they don't use it.

Dozens of countries, including Canada, Mexico, New Zealand, Norway, Turkey and others, allow the police or prison officials to use jammers.

Chinese and Indian schools use jammers to stop cheaters. Mexico allows jammers in churches and hospitals. And Pakistan allows jamming in banks and libraries.

Most countries, including the U.S., use jammers to thwart cell phone-triggered bomb attacks against government leaders. When President Obama walked down Pennsylvania Avenue after his inauguration, all cell phones were jammed in the area. The U.S. military uses jammers to stop roadside bomb attacks in Iraq.

In fact, the harsh laws against jammers in the U.S. apply to everyone except federal government officials. Which raises the question: Is that right?

U.S. prisons want to use jammers. So do police. And while we're at it, so do many movie theaters, restaurants and other businesses. Some individuals want to use jammers as well.

Who decided that only federal officials can be trusted with cell phone jammers?

How to enjoy a healthy World Cup

We are in the Center of World Cup 2010 now and this time it is in South Africa and as usual, the furnishings or ‘World Cup fever’ is overextension over the nations. It is the time for football admirers to accord abutment to their aggregation or adequate the bold by watching anon at the amphitheater or watching TV.

Believe it or not, some bloom botheration appear during the four-weeks World Cup and it’s not for the football amateur but the football admirers who are watching the bout from TV. While players are assuming their superior exercise and bloom on the pitch, the football admirers are acceptable to go for added end at the aforementioned time. The bloom problems including top claret pressure, affection advance or abridgement of beddy-bye ability appear in your way while watching the matches so let’s see some bloom tips on watching World Cup on TV.

1. Get abundant sleep

As the time of matches ability be altered from your place, you ability accept to watch aboriginal in the morning in adjustment to watch the reside advertisement of the match.The best way is to get abundant sleep. Get an aboriginal beddy-bye and set your all-overs about 15-30 account afore the bout starts. By this way you can antithesis your time and get abundant sleep.

2. Yield adapted meal

I accept that it is agreeable to yield our meal while watching TV but an important affair to accumulate in apperception is to yield adapted meal. Too abundant high-calorie food, acrid aliment and clutter aliment will not alone after-effects in diabetes but aswell high-blood pressure.

3. Watch your distance

Don’t break too abreast to the TV. Accomplish abiding you set able lighting in your allowance or watching breadth and in accepting a acceptable distance, use your faculty and move abroad from your TV if your eyes alpha to hurt. Watch from a ambit area you can calmly apprehend the argument on the awning after accept to squint.

4. Break relax and calm

Yes, football bout is abounding of affecting moments so beware! Pushing yourself too harder if watching World Cup on TV could aftereffect in high-blood burden and even affection attack. Besides that, it aswell brings all-overs and leads to added problems including auspicious you to smoke and overeating. So break relax and calm and don’t advance yourself too hard. I accept the football players charge to break focus and calm while arena and so do you.

Wrap Up

Watching football is an adequate moment abnormally if the aggregation which you abutment array goal. There is no abuse in adequate World Cup but consistently break active and convenance a advantageous way of watching TV or you ability accept to face the consequences.

Others

- Alcohol tea, not beer.

- Eat bake-apple instead of basics or crisps (though we feel that sitting in a pub at 2 AM bubbler tea and bistro beginning bake-apple ability could cause you added agitation than it’s worth).

- Ask for ice in your Guinness tea to abate booze content.

- Do not get into rounds. Alcohol alcohol-free beverages in between.

- If you feel like smoking, ablution your face, do addition exercises, try abysmal breath and alcohol baptize to alter your absorption from the urge.

- Reserve time to do some exercise. (Presumably if your ancillary is accepting its ass kicked)

- Strike a antithesis amid watching matches and accomplishing your amusing commitments. (Or maybe just allure some accompany forth and accomplish it a amusing commitment?

Home Security for Single Mothers

In today’s apple of ascent agitation and accretion abomination rates, it is important that all of us abide able-bodied adequate and defended from all sorts of dangers. Consequently, home security is absolutely one of the a lot of important issues to be discussed in the present situation. A lot of importantly, humans should feel chargeless and safe central their homes. Abnormally for accouchement no amount whatever the bearings is, affliction accept to be taken to ensure that they feel safe and abide chargeless of worries. It accept to be apparent that the problems of adults do not afflict their chastity and the aspect of childhood. The botheration of crisis generally turns out to be a above affair abnormally in the case of individual parents. In the case of individual mothers, parenting a adolescent or accouchement the affair of home aegis may accept added accent than added things.

Living after a bedmate is a botheration in abounding ways. However, with the actual measures adopted and things handled in an able abode the problems arising from individual parenthood may be done abroad with. First, the individual mother accept to be assured and feel anchored herself. The way she feels is traveling to accept a actual ample appulse on the way she will abundance her adolescent or children. So it is of absolute accent that the home anxious be defended from alien threats.

First, the blast accept to be able with the ability of addition identification software. This will advice her accept the hones to accept and the ones to reject. Moreover, she will aswell get to apperceive the amount from which she nay accept accustomed an adverse buzz alarm or message. However, nowadays, all corpuscle phones accept this facility. Therefore, this botheration should not be of abundant agitation and can be apparent calmly enough. Even the voicemail or the answering apparatus accept to accept a recorded bulletin that in no way reflects her position as a individual mother. Humans calling will again not be able to yield disproportionate advantage of her cachet as a individual mother. Objects calmly attainable to strangers and alien outsiders like mailboxes or abode confined should in no way announce her cachet as a individual mother, there are abounding artful who are on the anchor for accepting arbitrary advantages. In any way or the other, her weaknesses arising from her position as a individual ancestor should not be exposed.

The apparel and curtains, bindings accept to be shut down at night to abstain any abeyant burglar from analytical and demography a look. Such humans should never be accustomed a adumbration as to the weaknesses that appear out of individual parenting. Burglars and thieves consistently are on the anchor for such simple targets. In case a agent or a repairperson comes over, abnormally if he is a stranger, he should not be appear that you are a individual mother. Abounding humans generally try to yield disproportionate advantage of these situations. Cover up your weaknesses, present a adventurous foreground and your accouchement will reside advisedly and after fear.

Jam mobile phone signals in prisons, says inspector

Technology should be used to mobile phone signals jammers in prisons, an inspector at Britain's largest jail has said.

David Jamieson, chairman of Wandsworth prison's Independent Monitoring Board, says illegal phones fuel prison drug trading, bullying and gang problems.

Behind bars, phones can cost £400 each. He said the trade had been worth £9m in 2008, when 7,000 phones were seized.

The Prison Service says signal blocking is technically challenging and not quick, simple or cheap to implement.

Mr Jamieson told the BBC's Inside Out London programme he believed three times as many mobile phones were in circulation within prisons as had been seized.

Ever-smaller handsets allow phones to be smuggled in by prisoners, visitors or corrupt staff, he said.

Some are even thrown over prison walls.

'Pussyfooting around'

It would be impossible to stop them coming in, Mr Jamieson said, but signal-blocking technology would render them useless, preventing prisoners from using them to co-ordinate crime and intimidate witnesses on the outside.

Mr Jamieson said: "The technology... does exist. It would cost about £250,000 to equip a prison to jam calls. That would pay for itself quite easily over time."

However, he accused the government of "pussyfooting around" the issue.

The Ministry of Justice said it was already an offence to smuggle a phone into prison and that a new bill included laws intended to make it illegal to possess one in jail.

"The objective of this clause is to act as an additional deterrent to those who consider trafficking a mobile phone and/or its component parts into a prison, or to have them in their possession and to punish those who do," said a spokesman.

Viewers in London can see more on Inside Out on BBC1 on Monday at 1930 GMT, and across the UK on the BBC iPlayer.

article source:

http://news.bbc.co.uk/2/hi/uk_news/8373557.stm

Better city, better life! Shanghai’s transformation

The theme of Expo 2010 is “Better City, Better Life,” representing the common wish of the whole humankind for a better living in future urban environments. This theme represents a central concern of the international community for future policy making, urban strategies and sustainable development. In 1800, 2% of the global population lived in cities. In 1950, the figure raised to 29%, in 2000, almost half the world population moved into cities, and by 2010, as estimated by the United Nations, the urban population will account for 55% of the total human population.

The quest for a better life has run through the urban history of mankind. Through different sub-themes, Expo 2010 will create blueprints for future cities and harmonious urban life styles, providing an extraordinary educational and entertaining platform for visitors of all nations:

●Blending of diverse cultures in the city
●Economic prosperity in the city
●Innovations of science and technology in the city
●Remodelling of communities in the city
●Interactions between urban and rural areas

Across Shanghai, thousands and thousands of workers are transforming the city – repaving the roads and pavements, building new metro lines, repainting buildings, tearing down advertising hoardings, refurbishing the Bund and so on.

The city is spending a reported $45 billion (!!), making this probably the largest civic works project of all time.

The goal is to wow visitors to the 2010 World Expo, a biennial boondoggle which the rest of the world tends to ignore, but which Shanghai is treating like it is the equivalent of Beijing’s Olympics.

(Anyone remember the 2008 Expo in Zaragoza? Or the 2000 shindig in Hanover?)

Besides the non-stop building works, Shanghai is also ironing out some of its quirks. Residents are being encouraged not to hang laundry on the streets, to wear pajamas in public, or to spit. The employees on the metro are being told to wear uniforms. Bad English, or Chinglish, signs are being corrected.

Like Beijing, Shanghai is also going on an environmental drive, and the corporate pavilion at the Expo is made from used CD cases.

My favourite bit of Expo madness is that Haibao, the blue mascot of the event, has both a Twitter profile and Facebook page despite both website currently being censored by the Chinese government. Here’s Haibao in all his multinational glory.

Here are something I’ve been thinking about what I would like to see improve in the city:

1. Stop bikes and motorcycles from riding on the pavement. I’ve lost count of the number of times I’ve been honked from behind while walking, even when there is a street perfectly clear of traffic next to me.

2. Get drivers to slow down and to stop for pedestrians. This is a difficult one to enforce, but first-time visitors to Shanghai always complain about (a) very nearly being mowed down on zebra crossings and (b) enduring high-speed weaving taxi rides through town.

3. On that note – raise taxi prices. Shanghainese taxi drivers are always griping about how little money they make, and the low cost of taxis (£1 initial fee, 20p per kilometre) means that when it rains, no one can get a cab for hours. If the starting fee was higher, people would think twice about taking a cab when public transport will do. And perhaps English maps at bus stations would help tourists.

4. Increase hygiene inspection at restaurants. Chinese food, by and large, is pretty hygienic – it’s cooked in woks over a very high heat. But there are plenty of expensive, Western, restaurants in Shanghai that will make you ill.

5. Install proper rubbish bins. At the moment, everyone chucks their rubbish onto the street. Although it is collected pretty regularly, wouldn’t it be better to actually have bins?

6. Free Wifi. Pudong airport has already started providing free wifi. Other public spaces should follow suit.

http://en.expo2010.cn/

http://doorphone.informe.com/blog/2010/06/25/better-city-better-life-shanghais-transformation/

Wireless Doorbell's Reliability and Expense

The time has come for you to enjoy the fresh air on your back patio while you wait for your guests to arrive or be able to do yard work while you wait for the pizza delivery driver to show up. Doorbells are designed today to let you know when you have a visitor no matter where you are. Often, wired doorbells can't be heard in some areas within the house. Plus, when you decide to unplug your doorbell and install a wireless version, you can have your privacy when you truly want it by turning the thing off.

Reliability and Expense
Unlike much wireless technology, wireless video doorphones are extremely reliable. Maintenance involves little, if anything, more than replacing the batteries. In fact, many homeowners decide to purchase one when their original doorbell stops working—most frequently when the transformer that converts house current to low-voltage current has gone bad. If you're installing a new doorbell, a wireless one will circumvent the need to fish new electrical wiring through existing walls.

If you're building a new home, a wired doorbell will only create cumbersome, unneeded wiring when you're most likely seeking to create as simple and elegant a home as possible. Not much more than a glorified remote, a wireless doorbell is now comparable in price and creates more versatility for future upgrades.

Read more: http://www.servicemagic.com/article.show.Unplugging-Your-Doorbell-Wireless-Doorbells.13938.html#ixzz0rkaCi9JN

Tips To Remember To Keep Your Home Safe

There are many other steps and tips that you should follow while considering to keep your home and family safe. Firstly, you should always make sure that your windows and doors are properly secured. The obvious reason is that these are few places that a burglar will try to get in through. You should always keep your lights turned on. You can even get a watchdog for your home, and if you are planning to take a holiday or if you are away from your home for a period of time, you should let your neighbors know so that they can at least keep an eye on your house during your absence.

There are some other tips which you should keep in mind. You must get into the habit of locking your house every single time you leave. Never leave spare keys outside whereby they are accessible to susceptible intruders. Always lock your side gates, garage and shed. Never tell people that you are leaving unless it is required. Similarly do not gossip about the new commodities that you have purchased especially when you are leaving your home. You must not neglect to tell a few selected neighbors and friends that you are going outside so that they can keep a vigil over your house as and when they pass by your locality. You must prepare a list of all valuable items. . This last tip is especially important. The reason is that if there is a burglary despite implementing the best security measures and being extremely careful you can inform police about the assets that have been stolen. You can also keep a track of them and produce the necessary documents to the insurance company if in case you have insured them.

Read more:
http://www.espow.com/wholesale-security-alarm-systems.html

History Of The Doorbell

The doorbell began as a natural by-product of the door. After all, what better way to alert a host that visitors have arrived than to create an instrument that announces their arrival. Early examples of doorbells including a door knocker or a string attached to a bell. Both proved to be useful in their intended purpose so long as the host was near the door. Sound range and quality were not addressed until the advent of electricity. With the ushering in of this new technology, the doorbell was able to extend greater sound quality and range of sound throughout the house.
Beginning in the early 1900s, the electronic doorbell evolved from a simple buzzer sound to a number of musical door chimes. During this time period, it was very popular as it became one of the "Must-have" items of that time period. However, after 1965, the newness of electrical doorbells had worn off and the number of producers had diminished significantly.

Then, within the past 10 years, the doorbell has had a resurgence with overall producers extending into the teens and twenties. This resurgence has been sparked by the invention of the wireless doorbell and other sound advancements.

Doorbells are being sold and purchased on eBay at an astounding rate. The Doorbell is now listed as a hot item on their What’s Hot List. Sparked by the new interest in wireless doorbells, even wired doorbells have benefited as there is now an ever increasing list of different chimes and sounds ranging from popular old song favorites to more modern songs to even the option to record your own songs and greetings in cd quality format.

This surge in public interest has led to its present market state which features a never ending list of design features and other functions. Presently, you can get any number of designs for wired doorbell buttons and the wireless versions are steadily increasing as well. As far as more functions go, you can now purchase weatherproof wireless bell receivers that will allow you to hear the bell outside of your house whether you are on your deck or poolside.

The interest has even expanded beyond the basic doorbell features into other areas. You can now purchase a mail box doorbell which will alert you to when the mailman delivers the mail. There are even some doorbells which are set to illuminate the door area at night when someone rings the bell to allow you to see who is there. Furthermore, the simple doorbell has extended out to audio intercom and video doorbell intercom systems which help aid in the overall security and functionality of your home.

Bottom line the doorbell has managed to reinvent itself yet again. With the new interest in this area, we can all benefit by having a more functional doorbell that meets our ever increasingly, individual needs.

Amazing Video door phone

Recently, we launch a new product, video door phone, which integrate our video server. It is not only a product but also a solution. If some one is ringing your door phone, you can see who is standing in front of your house through the internet and 3G mobile phone simultaneously, even if you are not in your country. Also, you can talk to the person that you are not at home through the internet no mater where you are. In the emergency situation, you can record the image from our video server.

Prison cellphone jamming gets its first test in Maryland

As we wait for the Safe Prisons Communication Act to pass the House, word comes out of Maryland that FCI Cumberland will begin testing cellphone jammer technology this week. As you well know, critics of the plan have voiced concerns that the technology could interfere with emergency response and legitimate cell phone use near prisons, but the state is determined to put those criticisms to rest -- and to keep inmates from using contraband cellphones for prank calling the warden's wife, sexting folks on the outside, ordering brutal execution-style "hits" on people, and quite frankly bedeviling the law-abiding citizens that prisons are meant to protect. We can't help but wonder how HBO's Oz would have turned out differently if this had happened ten years ago.

Shut the Cell Up

Unsuspecting cellphone users may find themselves saying that more often now that cell phone jammers - illegal gizmos that interfere with signals and cut off reception - are selling like hotcakes on the streets of New York. "I bought one online, and I love it," said one jammer owner fed up with the din of dumb conversations and rock-and-roll ringtones.

"I use it on the bus all the time. I always zap the idiots who discuss what they want from the Chinese restaurant so that everyone can hear them. Why is that necessary?" He added, "I can't throw the phones out the window, so this is the next best thing."

Online mobile cell phone jammers seller Victor McCormack said he's made "hundreds of sales" to New Yorkers. "The interest has gone insane in the last few years. I get all sorts of people buying them, from priests to police officers."

Cell Phone Blockers come in a variety of shapes and sizes, from portable handhelds that look like cellphones to larger, fixed models as big as suitcases. Their sole goal is to zip inconsiderate lips. The smaller gadgets emit radio frequencies that block signals anywhere from a 50- to 200-foot radius. They range in price from $250 to $2,000.

But don't expect to find cell phone blockers at the local Radio Shack - they're against Federal Communications Commission regulations because they interfere with emergency calls and the public airwaves. They are illegal to buy, sell, use, import or advertise.

A violation means an $11,000 fine, but the FCC's Enforcement Bureau has yet to bust one person anywhere in the country. "This is not a crime that they're going after," said Rob Bernstein, deputy editor at New York City-based Sync magazine.

He said mobile cell phone jammers are here, and their use is multiplying.

"Right now, there's a growing curiosity about jammers in the United States and New York," Bernstein said. "There's no better way to shut up a loudmouth on the phone, so people definitely want them and are finding ways to get them." One way is at a spy shop on Third Avenue, which sells medium-sized cell phone signal jammers out of a back room for $1,500. The sales clerk there said he had sold jammers to a 50-year-old man who bought one to use on the Long Island Rail Road, and to restaurateurs.

Folks who run auto auctions also buy them to stop people from chit-chatting about prices and rigging their bids, the clerk said. An employee at a West Village spy store said the shop also sells phone jammers, but only to people from other countries.

One local purchaser bought a portable phone jammer last year, and said he likes using it at Roosevelt Field mall on Long Island. "One time I followed this guy around for 20 minutes," he said. "I kept zapping him and zapping him, until finally he threw the phone on the floor. I couldn't stop laughing. It was so cool."

Portable cell phone jammers were first developed to help government security forces avert eavesdropping and thwart phone-triggered bombings. But by the late 1990s they were being sold to the public. There are suspicions that some hotel chains employ cell phone signal jammers to cut down on guests' cellphone use and boost in-room phone charges.

http://www.cell-phone-jammers.com/cellphonejammers.html

Cell Phone Jamming Legal Issues

In the United States, United Kingdom, Australia and many other countries, blocking cell-phone services (as well as any other electronic transmissions) is against the law. In the United States, cell-phone jamming is covered under the Communications Act of 1934, which prohibits people from "willfully or maliciously interfering with the radio communications of any station licensed or authorized" to operate. In fact, the "manufacture, importation, sale or offer for sale, including advertising, of devices designed to block or jam wireless transmissions is prohibited" as well.

Cell Phones Signal Jammer is seen as property theft, because a private company has purchased the rights to the radio spectrum, and jamming the spectrum is akin to stealing the property the company has purchased. It also represents a safety hazard because jamming blocks all calls in the area, not just the annoying ones. Jamming a signal could block the call of a babysitter frantically trying to contact a parent or a someone trying to call for an ambulance.

The Federal Communications Commission is charged with enforcing jamming laws. However, the agency has not yet prosecuted anyone for cell-phone jamming. Under the U.S. rules, fines for a first offense ca­n range as high as $11,000 for each violation or imprisonment for up to one year, and the device used may also be seized and forfeited to the government.

In most countries, it is illegal for private citizens to jam cell-phone transmission, but some countries are allowing businesses and government organizations to install jammers in areas where cell-phone use is seen as a public nuisance. In December 2004, France legalized cell-phone jammers in movie theaters, concert halls and other places with performances. France is finalizing technology that will let calls to emergency services go through. India has installed jammers in parliament and some prisons. It has been reported that universities in Italy have adopted the technology to prevent cheating. Students were taking photos of tests with their camera phones and sending them to classmates.

With phones ringing in movies, weddings and classrooms, it's no wonder people want to tone down the intrusion. So what legally can be done to stop annoying cell-phone use?

http://www.espow.com/wholesale-broad-spectrum-cell-phone-jammer.html

Cell Phone Jammer Applications

Cell phone jamming devices were originally developed for law enforcement and the military to interrupt communications by criminals and terrorists. The bombs that blew up commuter trains in Spain in March 2004, as well as blasts in Bali in October 2002 and Jakarta in August 2003, all relied on cell phones to trigger explosives. It has been widely reported that a cell-phone jammer thwarted an assassination attempt on Pakistani President Musharraf in December 2003. When President Bush visited London in November 2004, it was reported that British police considered using cell phone jammers to protect the president's motorcade through London.

During a hostage situation, police can control when and where a captor can make a phone call. Police can block phone calls during a drug raid so suspects can't communicate outside the area. Cell-phone jammers can be used in areas where radio transmissions are dangerous, (areas with a potentially explosive atmosphere), such as chemical storage facilities or grain elevators. The TRJ-89 jammer from Antenna System & Supplies Inc. carries its own electrical generator and can block cellular communications in a 5-mile (8-km) radius.

Corporations use jammers to stop corporate espionage by blocking voice transmissions and photo transmissions from camera phones. On the more questionable end of the legitimacy spectrum, there are rumors that hotel chains install jammers to block guests' cell-phone usage and force them to use in-room phones at high rates.

More info:
http://www.espow.com/wholesale-security-jammer.html

Inside Cell Phone Jammers

Electronically speaking, cell-phone jammers are very basic devices. The simplest just have an on/off switch and a light that indicates it's on. More complex devices have switches to activate jamming at different frequencies. Components of a cell phone jammer include:

Antenna
Every jamming device has an antenna to send the signal. Some are contained within an electrical cabinet. On stronger devices, antennas are external to provide longer range and may be tuned for individual frequencies.

Circuitry
The main electronic components of a jammer are:

• Voltage-controlled oscillator - Generates the radio signal that will interfere with the cell phone signal
• Tuning circuit - Controls the frequency at which the jammer broadcasts its signal by sending a particular voltage to the oscillator
• Noise generator - Produces random electronic output in a specified frequency range to jam the cell-phone network signal (part of the tuning circuit)
• RF amplification (gain stage) - Boosts the power of the radio frequency output to high enough levels to jam a signal

Power supply
Smaller jamming devices are battery operated. Some look like cell phone and use cell-phone batteries. Stronger devices can be plugged into a standard outlet or wired into a vehicle's electrical system.

• ­ Check your phone - If the battery on your phone is okay, and you'd like to continue your conversation, try walking away from the area. You may be able to get out of the jammer's range with just a few steps.

Cell Phone Jamming Device

cell phone jammer overpower the cell phone by transmitting a signal on the same frequency and at a high enough power that the two signals collide and cancel each other out. Cell phones are designed to add power if they experience low-level interference, so the jammer must recognize and match the power increase from the phone.

Cell phones are full-duplex devices, which means they use two separate frequencies, one for talking and one for listening simultaneously. Some jammers block only one of the frequencies used by cell phones, which has the effect of blocking both. The phone is tricked into thinking there is no service because it can receive only one of the frequencies.

Less complex devices block only one group of frequencies, while sophisticated jammers can block several types of networks at once to head off dual-mode or tri-mode phones that automatically switch among different network types to find an open signal. Some of the high-end devices block all frequencies at once, and others can be tuned to specific frequencies.

To jam a cell phone, all you need is a device that broadcasts on the correct frequencies. Although different cellular systems process signals differently, all cell-phone networks use radio signals that can be interrupted. GSM, used in digital cellular and PCS-based systems, operates in the 900-MHz and 1800-MHz bands in Europe and Asia and in the 1900-MHz (sometimes referred to as 1.9-GHz) band in the United States. Jammers can broadcast on any frequency and are effective against AMPS, CDMA, TDMA, GSM, PCS, DCS, iDEN and Nextel systems. Old-fashioned analog cell phones and today's digital devices are equally susceptible to jamming.

The actual range of the jammer depends on its power and the local environment, which may include hills or walls of a building that block the jamming signal. Low-powered jammers block calls in a range of about 30 feet (9 m). Higher-powered units create a cell-free zone as large as a football field. Units used by law enforcement can shut down service up to 1 mile (1.6 km) from the device.

More :
http://en.wikipedia.org/wiki/Mobile_phone_jammer

Cell Phone Jamming Basics

Disrupting a cell phone is the same as jamming any other type of radio communication. A cell phone works by communicating with its service network through a cell tower or base station. Cell towers divide a city into small areas, or cells. As a cell-phone user drives down the street, the signal is handed from tower to tower.

A cell phone jammer device transmits on the same radio frequencies as the cell phone, disrupting the communication between the phone and the cell-phone base station in the tower.


It's a called a denial-of-service attack. The jammer denies service of the radio spectrum to the cell-phone users within range of the jamming device.

Read more:
http://electronics.howstuffworks.com/cell-phone-jammer1.htm

How A Cell Phone Jammer Work?

Why cell phone jammer exist?

Cell phones are everywhere these days. According to the Cellular Telecommunications and Internet Association, about 195 actor humans in the United States had cell-phone account in October 2005. And corpuscle phones are even added all-over in Europe.

It's abundant to be able to alarm anyone at anytime. Unfortunately, restaurants, cine theaters, concerts, arcade malls and churches all ache from the advance of corpuscle phones because not all cell-phone users apperceive if to stop talking. Who hasn't seethed through one ancillary of a chat about an abundantly claimed bearings as the anchorperson shares affectionate data with his acquaintance as able-bodied as anybody abroad in the area?

While a lot of of us just beef and move on, some humans are in fact traveling to extremes to retaliate. Corpuscle phones are basically handheld two-way radios. And like any radio, the arresting can be disrupted, or jammed.

In this article, you'll see how cell phone jammers plan and apprentice about the amends of their use.

Related:
http://electronics.howstuffworks.com/cell-phone-jammer1.htm

Mexico to block cell phone signals in prisons

Mexican authorities will install mobile Cell Phone Jammer devices in prisons to curb use of cell phones by inmates and check crimes.

Of the total 429 jails, devices will be installed in 78 prisons which house 75 percent inmates of the country. The move will help in checking crimes such as extortion and kidnapping, mostly carried out by prisoners with the help of cell phones, Reforma newspaper reported.

The report said that 85 percent of the mobile phones are brought to the prisons by security guards and the rest by visitors with clearance from the authorities. Guards also sell mobile phones to inmates and collect a monthly 'rental' from them.

http://sify.com/news/mexico-to-block-cell-phone-signals-in-prisons-news-international-kgbuOeaccaa.html

A cell phone jammers is a accessory that emits signals in the aforementioned abundance ambit that corpuscle phones use, finer blocking their transmissions by creating able interference. Someone application a corpuscle buzz aural the ambit of a jammer will lose signal, but accept no way of alive a jammer was the reason. The buzz will artlessly announce poor accession strength.

With the all-over use of corpuscle phones, a backfire has occurred. While some humans convenance corpuscle buzz etiquette, abounding others audibly altercate their private, able or banal business in accessible areas, banishment anybody adjacent to listen. On trains, subways, buses, in the grocery market, arcade capital and café, humans are aggravating adolescent citizens with their ceaseless chit-chat. This has acquired some humans to yield affairs into their own hands. With a Cell Phones Signal Jammer in purse or pocket, jabbermouths can be angry off with the cast of a about-face — and they won't be able to reconnect as continued as the jammer is activated unless they move far abundant abroad from the source.

Installing a wireless video doorbell intercom

Installing a wireless video door phone decidedly increases your adventitious of alone greeting safe visitors. If you accept a wireless video aperture buzz installed, every time a aggregation rings the doorbell, an angel of them appears on the awning amid cautiously aural your home. You can again authority a two-way chat with the aggregation area you will be able to barometer his absorbed while searching at him. If he says he’s with the cable company, but keeps putting his duke cautiously in his pocket, again you accept all the clues you charge to alarm the police. And it’s all acknowledgment to your wireless video aperture phone.

Wireless video door phone intercom do not alone actuate if anyone rings the bell. They can be acclimated continuously to adviser goings on alfresco your home. This can be abnormally accessible if you are a celebrity or accessible amount or if you reside in a alarming adjacency area abomination runs rampant. Wireless video aperture phones aswell address over 300 anxiety aural band of site, acceptance you a abundant appearance from alfresco your home. It’s consistently a acceptable abstraction to analysis with your wireless video aperture buzz afore abrogation the bounds in case something that you cannot apprehend or see from your window is accepted alfresco the aegis of your home.

Wireless video aperture phones are aswell not bound to day time hours. After all, if do burglars, rapists and murders a lot of like to bang if not in the asleep of night? Infrared camera technology with your wireless aperture buzz allows you to adviser visitor’s faces and beheld cues, as able-bodied as affaire alfresco your abode even in the asleep of night.

3.5 inch video door phone intercom are aswell frequently acclimated in appointment settings. Often offices are home to awful admired or defended advice or to humans who ability be on the victim account of hit men or added belled criminals. With a wireless video aperture phone, appointment workers can feel safe and defended abundant to get their plan done after annoying if the next being to footfall through that aperture will be a criminal.