how does the radio frequency security tags that department stores normally use on the clothing work?
98150
The radio tags that you are referring to are typically called RFID tags, or radio frequency identification tags.  It consists of a small antenna and a microchip which is a radio transponder.  \n\nWhen you pass through the detector at the door, the detector is continually pulsing a radio signal.  The radio signal is picked up by the antenna in the tag, which generates a very small amount of current to power the microchip.  The microchip then transmits back an identification code that is received by the detector.  If that tag isn't supposed to be there, then  the alarm goes off.\n\nYou will notice at the check-out counter that the cashier has either a device to remove the RFID tag or passes it over a device next to the barcode scanner that disables it.  It works just like the detector, but it sends a special code to the RFID microchip to permanently disable itself.  With the tag disabled, it doesn't transmit anything to the detector and you aren't stopped by your friendly Wal-mart greeter to check your bags for something that you presumably have stolen.
969954
I think that metal detectors just work by setting up a magnetic field. When the apparatus move over a location that has a magnetic material a flux is produced that induces an electric current in the metal detector, activating a sensor.\n\nIf this is the case (i'm 95% sure it is), then the only factors affecting it's quaility would be within the machine itself as far the smallest current that activates the sensor.\n\nHeat and moisture would not change the magnetic field (moisture might theoretically alter the detectors magnetic field a little bit, but certainly not enough to measure). The both give the same result.
778854
Electromagnetic shielding\n\nElectromagnetic shielding is the process of limiting the flow of electromagnetic fields between two locations, by separating them with a barrier made of conductive material. Typically it is applied to enclosures, separating electrical devices from the 'outside world', and to cables, separating wires from the environment the cable runs through. Electromagnetic shielding used to block radiofrequency electromagnetic radiation is also known as RF shielding.\n\nThe shielding can reduce the coupling of radio waves, visible light, electromagnetic fields and electrostatic fields, though not static magnetic fields. (A conductive enclosure used to block electrostatic fields is also known as a Faraday cage.) The amount of reduction depends very much upon the material used, its thickness, and the frequency of the fields of interest.\n\nMaterials used\nTypical materials used for electromagnetic shielding include sheet metal, metal mesh, ionized gas, plasma and aluminum foil. Any holes in the shield or mesh must be significantly smaller than the wavelength of the radiation that is being kept out, or the enclosure will not effectively approximate an unbroken conducting surface.\n\nAnother commonly used shielding method, especially with electronic goods housed in plastic enclosures, is to coat the inside of the enclosure with a metallic ink or similar material. The ink consists of a carrier material loaded with a suitable metal, typically copper or nickel, in the form of very small particulates. It is sprayed on to the enclosure and, once dry, produces a continuous conductive layer of metal, which can be electrically connected to the chassis ground of the equipment, thus providing effective shielding.\n\n\n[edit] Example applications\nOne example is a shielded cable, which has electromagnetic shielding in the form of a wire mesh surrounding an inner core conductor. The shielding impedes the escape of any signal from the core conductor, and also signals from being added to the core conductor. Some cables have two separate concentric screens, one connected at both ends, the other at one end only, to maximise shielding of both electromagnetic and electrostatic fields.\n\nThe door of a microwave oven has a screen built into the glass of the window. From the perspective of microwaves (with wavelengths of 12 cm) this screen finishes a Faraday cage formed by the oven's metal housing. Visible light, with wavelengths ranging between 400nm and 900nm, passes easily between the wires.\n\nRF shielding is also used to prevent access to data stored on RFID chips embedded in various devices, such as biometric passports.\n\n\n[edit] How RF shielding works\nElectromagnetic radiation consists of coupled electric and magnetic fields. The electric field produces forces on the charge carriers (i.e., electrons) within the conductor. As soon as an electric field is applied to the surface of an ideal conductor, it generates a current that causes displacement of charge inside the conductor that cancels the applied field inside, at which point the current stops.\n\nSimilarly, varying magnetic fields generate current vortices that act to cancel the applied magnetic field. (The conductor does not respond to static magnetic fields, so static magnetic fields can penetrate the conductor freely.) The result is that electromagnetic radiation is reflected from the surface of the conductor: internal fields stay inside, and external fields stay outside.\n\nSeveral factors serve to limit the shielding capability of real RF shields. One is that, due to the electrical resistance of the conductor, the excited field does not completely cancel the incident field. Also, most conductors exhibit a ferromagnetic response to low-frequency magnetic fields, so that such fields are not fully attenuated by the conductor. Any holes in the shield force current to flow around them, so that fields passing through the holes do not excite opposing electromagn
871865
Radio Frequency Identification.  This is where passive electronic tags are put into goods (e.g. think like the security strips at the store, but smarter in that they contain way more information or perhaps a non-powered version of the electronic toll pass in your car). The goods are passed through an electronic gantry that scans the codes and passes along the information.  That way you know everything that is in a pallet, container or box - how many, what color, what size, where they are from, where they are going.  All that time spent counting and categorizing by person is now done via technology. \n\n\nPros:\n1. Faster inventory velocity through the supply chain\n2. Lower costs of logistics\n3. Higher visibility of goods when in transit\n4. Lower shrinkage due to less container packing/unpacking/inspection\n5. Lower inventory levels needed as inventory can get more efficient. \n6. Lower total cost to consumer\n\nCons:\n1. Higher initial costs to logistics suppliers (who have to buy RFID systems)\n2. Fewer safeguards.  RFID tagged containers are sealed, which means less eyes on the container from origin to destination.  US Port Security acts means they may be inspected once they reach the US port, but it is only on a sample basis.\n3. Higher barrier to entry against competition as Walmart builds its cost advantage against competitors (i.e. you start to worry about anti-trust issues). \n4. Concerns that success at commercial level would spill over to personnel level, which would infringe upon personal privacy issues. However, electronic building passes already use this technology.
1032753
There are companies, such as e.g. VeriSign, that test whether websites that offer items against payment, have taken all reasonable measures to ensure the privacy of such financial information, such as credit card info, social security number, etc.\nMany online vendors use the marks and emblems to show that their websites are secure. Although there are regretfully some that just add the marks to their site without having undergone the testing.\nIf you are not sure about a certain site, you could always go to the website of the company, whose mark/emblem is displayed and investigate the vendor in question. You should either be able to obtain enough info to put your mind at ease or to tell you to best leave that particular one be.
404057
Their website has many different items to chose from. And they practice good business etiquette.\n\nLink (just copy & paste): http://www.anytimecostumes.com/costumes/edt.html
1061441
Only that you keep the string hidden so that no one knows you are wearing one.  Also, that you keep it changed often so that you don't have any leakage.  :)
360678
I work retail. It's to keep them from getting stolen. Lots of $$ has been lost from CD's and DVD's and such being stolen. But, it's sad that even cashiers have a hard time taking that plastic around them off. Some really struggle and they even have the device that's meant to help lol
684027
These are "smart tags."
1034912
F.C.C. regulations declare that stations on the "radio" must identify themselves by call letters every hour of operation. And on HAM radios its every 10 minutes. \nStation identification is used because of the sheer number of signals available over the air. Not only are there radio and television signals being broadcast, there are also two-way radio signals from police, emergency crews and private companies as well as amateur radio signals. Early radio operators recognized the need for anyone listening to a signal over the air to be able to tune in a specific time and immediately know what station was being heard and where the signal was originating from.\n\nAccording to United States law, the FCC can fine or reprimand a station for failing to make the appropriate identification.\n\nSo yes they infact do, you just might not hear it now-a-days as obvious as you used to.
384277
Radio Frequency Identification (RFID) is an automatic identification method, relying on storing and remotely retrieving data using devices called RFID tags or transponders. An RFID tag is a small object that can be attached to or incorporated into a product, animal, or person. RFID tags contain silicon chips and antennas to enable them to receive and respond to radio-frequency queries from an RFID transceiver. Passive tags require no internal power source, whereas active tags require a power source.\n\n\nFor a very detailed information on RFID, please visit the source page.
340206
The scanner sends out a laser beam that reflects against the barcode on the object. The scanner is programmed to recognize the reflections of barcodes and use those to identify the product.
471001
OK civilian cops need a reason to pull you over un like what the second person said.  The can stop you because there are numbers on the tag and when the officer ran you plate the more then likely came back as expired, the DMV should have put something in computer for the cops so it would say that you had a temp tag but more then likely it did not make it into the comp and the cop needed to see the numbers on the tag and run those to make sure it was not stolen from another vehicle.  there are also regs on how it should be displayed so if it was done wrong he could have stopped you for that
658674
It is made of quilted material, usually cream colored... that gives some padding to the torso, arms and hands... and it is a jacket that is put onto the body with the arms into the extra long sleeves and the collar goes up to the neckline and the length goes down to the hip line.  It is tied in the back and the sleeves have long belts on each arm that when you cross your arms in the front these two belts are pulled tightly behind you and they are fastened into snap and buckle closures that you CANNOT get out of.  Your arms and hands are totally enclosed and they are tied tightly across your chest.  This is to prevent you from getting loose and doing harm to yourself.  \n\nThis device was used to restrain people with mental conditions that could not control their actions of self destruction.  It is seldom used today.  Hope this helps you to understand what a straight jacket is... An RN nurse...
66062
Nowadays, technology in using high-tech cameras fixed with a type of lens called PF LENS, which can see through clothings. The PF LENS is able to see through most types of clothes, for example, thin clothes, tight clothes, sun dresses, swimsuits and so forth. Be awared that this means that the person taking a snap on you can actually see your naked body both "upper & underpart" through the external garment. In other words, the PF Lens allows the camera man to "see through" someone's clothes.\n\nSuggest that whenever you suspect some strangers holding a camera or Digicam pointing at you, try to avoid facing him (face to face). Quickly use your handbag or any shopping bags in hand to cover your whole front body (in case), Next, escape from the scene as soon as possible. This is to save a situation from landing yourself into the hands of evil. Recently, many girls and housewives' naked photo were vastly distributed in the internet websites without them knowing. Perverts intentionally move around places where ladies usually frequent and took their nude shots.
159721
Infra red - used for heating\n\nMicrowaves and radar - used for cooking and, erm, for radar. :) 802.11b/g LANs, bluetooth, portable telephones, baby monitors, satellite TV, satellite communications, and a host of other devices also operate in these frequencies\n\nTV and FM radio\n\nShortwave radio\n\nAM radio\n\nAircraft and Shipping radio bands \n\nExtremely low frequency -- very long wavelengths can be used to punch small amounts of information through to a receiver in extreme conditions.  The navy had an ELF system for the purpose of giving orders to launch nukes to submarines.  This system has reportedly been abandoned.\n\nSee "sources".  First source is an introductory web page to the electromagnetic spectrum from NASA.  Second source is information on the Navy's project ELF
736119
There really is no such thing as a "typical" RFID tag, and the read range of passive tags depends on many factors: the frequency of operation, the power of the reader, interference from other RF devices and so on. In general, low-frequency tags are read from a foot (0.33 meter) or less. High-frequency tags are read from about three feet (1 meter) and UHF tags are read from 10 to 20 feet. Where longer ranges are needed, such as for tracking railway cars, active tags use batteries to boost read ranges to 300 feet (100 meters) or more.