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Our most commonly asked questions by grades 9-12 are:
 Are Cell Phone Calls Private?
 Why can't you use cell phones in hospitals or airplanes?
 Do cell phones cause brain cancer?
 What is a V-Chip?
 How does a V-Chip work?
 What is Digital Television (DTV)?
 What is unacceptable language for radio and television?
 What is Obscene Speech?
 Why do all FM radio stations end in an odd number?
 How does my pager work?
 How does a fax machine work?
Are Cell Phone Calls Private?
Cell phones are actually two-way radios that connect the telephone with a nearby cellular tower, and through that tower to the regular wired telephone system.††Because the cell phone uses a radio signal, it theoretically can be listened to†with the right radio equipment.† However, laws have been enacted that prohibit bringing such equipment into the country or using such equipment without special permission.† In addition, cell phones have a very limited range, and many phones share the same radio frequencies.† Consequently, the likelihood of someone†intercepting a cell phone call is almost nonexistent in this country, but possible.
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cell phones restricted Why canít you use cell phones in hospitals or airplanes?
Some of the places that you should never use your mobile phone are inside hospitals and airplanes. When you make or receive calls, electromagnetic waves are sent through the air. Hospitals have a lot of electronic devices that monitor patient's heartbeats and other thing when they are getting surgery or when they are recovering from an illness. When electromagnetic waves try to go through them, the devices sometimes stop working. You can imagine how bad that would be for doctors and nurses in hospitals who are trying to save lives. That's why we should never use mobile phones inside of a hospital.
It's the same thing in airplanes because they use computers to fly through the air. If the computers don't work properly, the airplane may not go the right direction or fly at the right height, or they may even crash! Next time you get on a plane, make sure you turn off your mobile phone so everyone can have a safe flight.

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Do cell phones cause brain cancer?
There is no scientific evidence to date that proves that wireless phone usage can lead to cancer or a variety of other health effects, including headaches, dizziness or memory loss. However, studies are ongoing and key government agencies, such as the Food and Drug Administration (FDA) continue to monitor the results of the latest scientific research on this topic. In 1993," the FDA, which has primary jurisdiction for investigating mobile phone safety, stated that it did not have enough information at that time to rule out the possibility of risk, but if such a risk exists, "it is probably small." The FDA concluded that there is no proof that cellular telephones can be harmful, but if individuals remain concerned several precautionary actions could be taken, including limiting conversations on hand-held cellular telephones and making greater use of telephones with vehicle-mounted antennas where there is a greater separation distance between the user and the radiating antennas. The Web site for the FDA's Center for Devices and Radiological Health provides further information on mobile phone safety: www.fda.gov/cdrh/phones/index.html.
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"v" chip What is a V-Chip?
The V-chip is a technology that lets parents block television programming they don't want their children to watch. http://www.fcc.gov/parents/
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tv ratings How does a V-Chip work?
The V-Chip electronically reads television-programming ratings and allows parents to block programs they believe are unsuitable for their children. (Ratings appear in the corner of your television screen during the first 15 seconds of a program and in TV programming guides). This rating is encoded into the program, and the V-chip technology reads the encoded information and blocks shows accordingly. Using the remote control, parents can program the V-chip to block certain shows based on their ratings.
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digital tv What is Digital Television (DTV)?
Digital Television is a new system of bringing TV signals to your TV set. The DTV signals sent from TV stations are in digital modulation format rather than in the analog modulation format which has been used since television began. You can see digital TV sets on sale at most electronics and large appliance stores right now. They are the ones with the wide screens similar in shape to the screen in a movie theater. Most of these DTV sets are still pretty expensive but the prices are coming down rapidly. DTV allows TV stations to provide you with new and different services that were not available with the old analog system. Probably the most important DTV service is the delivery to your home of High Definition TV (HDTV) signals. Pictures on a DTV set with an HDTV signal provide you with an unusually bright, clear, sharp and lifelike picture in a wide screen format with surround sound audio capability. All full-power TV broadcast stations were required to switch from analog to digital broadcasting by June 12, 2009.
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What is unacceptable language for radio and television?
It is a violation of federal law to broadcast obscene programming at any time. It is also a violation of federal law to broadcast indecent programming during certain hours. Congress has given the Federal Communications Commission (FCC) the responsibility for administratively enforcing the law that governs these types of broadcasts. The Commission may revoke a station license, impose a monetary forfeiture, or issue a warning, for the broadcast of obscene or indecent material. http://www.fcc.gov/cgb/consumerfacts/obscene.html
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people swearing and fighting What is Obscene Speech?
Obscene speech is not protected by the First Amendment and cannot be broadcast at any time. To be obscene, material must meet a three-prong test: (1) an average person, applying contemporary community standards, must find that the material, as a whole, appeals to the prurient interest; (2) the material must depict or describe, in a patently offensive way, sexual conduct specifically defined by applicable law; and (3) the material, taken as a whole, must lack serious literary, artistic, political, or scientific value.
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Why do all FM radio stations end in an odd number?
FM radio stations all transmit in a band between 88 megahertz (millions of cycles per second) and 108 megahertz. The band is divided into 100 channels, each 200 kHz (0.2 MHz) wide. The center frequency is located at 1/2 the bandwidth of the FM Channel, or 100 kHz (0.1 MHz) up from the lower end of the channel. For example, the center frequency for Channel 201 (the first FM channel) is 88.0 MHz + 0.1 MHz = 88.1 MHz. So there can be a station at 88.1 megahertz, 88.3 megahertz, 88.5 megahertz, and so on. The 200-kilohertz spacing, and the fact that they center on odd numbers is completely arbitrary and was decided by the FCC. In Europe, the FM stations are spaced 100 kilohertz apart instead of 200 kilohertz apart, and they can end on even or odd numbers.
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image of pagerHow does my pager work?
A pager is like a FM radio that is tuned to one frequency. (The FCC assigns each paging company specific radio frequencies on which to broadcast their paging signals.) Your pager will "listen" for a unique code within this paging signal. When the code reaches you and your pager "hears" its signal, it decodes it and displays the numeric or word message for you. The frequency of a pager is not within the broadcast bands, and cannot be heard on a regular radio.
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image of fax machineHow does a fax machine work?
The idea of fax machines has been around since 1842, when Alexander Bain invented a machine capable of receiving signals from a telegraph wire and translating them into images on paper. Fax machines provide an easy way to send documents to any phone number equipped with a fax machine. A fax machine works by scanning each outgoing page and converting the image into a series of light and dark dots. This pattern is then translated into audio tones, and sent over regular phone lines. The receiving fax "hears" the tones, pieces the grid together, and prints the total number of dots. The resulting document is a black and white likeness of the original page.
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On April 3, 1973, Martin Cooper made the first cellular phone call.



last reviewed/updated on 07/17/09 

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