how do cell phones work?
542349
Cell phones are complex, so it depends on what part you want to know about.  Since all microphones convert sound into an electrical signal, I'll skip that.  What makes cell phones special is that you can move around (even in a vehicle across your city) and, theoretically, not lose your signal.  \n\nHow is that possible?  There is not one big tower in each city that is taking all the calls from the thousands of people.  Instead, the phone company divides each city into "cells" that each have their own base station.  The base station receives the signal from your phone and transmits it back to the central office, which is connected to the regular phone network.  The area of a cell is usually only a couple square kilometers.  When you leave a cell, the base station senses that and moves control into the new cell that you're entering.  \n\nFurther, this is efficient because these high frequency signals cannot travel very far.  Thus, whatever frequency you're using on your phone can be reused just a couple of cells away.  \n\nMoreover, each cell can only handle a few dozen or so people.  That's why sometimes you'll see "network busy" when you try to make a call.  Or if you enter a new cell that is operating at capacity, the network will drop your call.  \n\nSo that's what makes cell phones special.  The rest (converting sound to electromagnetic waves, sending the waves wirelessly) is not new to cell phones.\n\nIf you have any more specific questions, please let me know.
873537
When a person speaks into a telephone, the sound waves created by his voice enter the mouthpiece. An electric current carries the sound to the telephone of the person he is talking to. A telephone has two main parts: (1) the transmitter and (2) the receiver.\nThe Transmitter of a telephone serves as a sensitive "electric ear." It lies behind the mouthpiece of the phone. Like the human ear, the transmitter has an 14 eardrum." The eardrum of the telephone is a thin, round metal disk called a diaphragm. When a person talks into the telephone, the sound waves strike the diaphragm and make it vibrate. The diaphragm vibrates at various speeds, depending on the variations in air pressure caused by the varying tones of the speaker's voice.\n\n\nBehind the diaphragm lies a small cup filled with tiny grains of carbon. The diaphragm presses against these carbon grains. Low voltage electric current travels through the grains. This current comes from batteries at the telephone company. The pressure on the carbon grains varies as sound waves make the diaphragm vibrate. A loud sound causes the sound waves to push hard on the diaphragm. In turn, the diaphragm presses the grains tightly together. This action makes it easier for the electric current to travel through, and a large amount of electricity flows through the grains. When the sound is soft, the sound waves push lightly on the diaphragm. In turn, the diaphragm puts only a light pressure on the carbon grains. The grains are pressed together loosely. This makes it harder for the electric current to pass through them, and less current flows through the grains.\n\n\nThus, the pattern of the sound waves determines the pressure on the diaphragm. This pressure, in turn, regulates the pressure on the carbon grains. The crowded or loose grains cause the electric current to become stronger or weaker. The current copies the pattern of the sound waves and travels over a telephone wire to the receiver of another telephone.\n\n\nThe Receiver serves as an "electric mouth." Like a human voice, it has "vocal cords." The vocal cords of the receiver are a diaphragm. Two magnets located at the edge of the diaphragm cause it to vibrate. One of the magnets is a permanent magnet that constantly holds the diaphragm close to it. The other magnet is an electromagnet. It consists of a piece of iron with a coil of wire wound around it. When an electric current passes through the coil, the iron core becomes magnetized. The diaphragm is pulled toward the iron core and away from the permanent magnet. The pull of the electromagnet varies between strong and weak, depending on the variations in the current. Thus, the electromagnet controls the vibrations of the diaphragm in the receiver.\nThe electric current passing through the electromagnet becomes stronger or weaker according to the loud or soft sounds. This action causes the diaphragm to vibrate according to the speaker's speech pattern. As the diaphragm moves in and out, it pulls and pushes the air in front of it. The pressure on the air sets up sound waves that are the same as the ones sent into the transmitter. The sound waves strike the ear of the listener and he hears the words of the speaker.
732764
Are they cell phones?
1120814
If you are talking on one, they can trace it to which cell tower it is using,  alot closer in major cities,  a larger distance in rual areas.\n\nThere are some phones now that do have GPS tracking ability but they are still rare.  But with those, yes to the very spot they are sitting.
15472
Somewhat. Since cellphone services support short message services which is also like paging, it relieves users to carry both cellphones and beepers. However, some professionals like medical staff sill use pagers because messages qickly pass through to the users.
214904
normally they work with antennas, electromagnetic fields propagation and communications systems. It has to do a lot with electrical signals and electrical behavior of components in the high frequency spectrum (normally above 9MHz, but radio signals of a few KHz might also be of interest)
934521
I would agree that "howstuffworks" does a pretty good job.  The point is that "cellular" comes from the "cells" by which geographic areas are divided for the phone service.\nhttp://electronics.howstuffworks.com/cell-phone.htm
303504
You can get the settings for your cell phone at either your cell phone providers website, or technical support.\nThey will either email, text message, or automatically send them to your phone.\nCare of internet surfing on your cell phone, you will need to make sure you don't rack up charges for data transfer. Look at your cell phone package, and see if it includes a data package and the rates for information transfer.
396301
They just make phones as far as I know.
275478
Cell phones, TV and radio reception
992673
I think called as bag phones or Mobile phone....\n\nwant to see Histroy of Mobile phone...\nsee this link\n\nhttp://en.wikipedia.org/wiki/History_of_mobile_phones
574269
John O's answer is pretty good, except that microwave frequencies have a harder time travelling a far distance compared to lower frequencies.  \n\nHowever, a lot of people said that cell phones use satellites, and that's simply wrong.\n\nAnyway, it's not only cell phones that can interfere with instruments, but any electronics.  I've read where a handheld calculator would skew the instruments when the buttons were pushed.  That's why you can't have any electronic device on when the plane is taking off or landing, not just cell phones.  As far as the limits for getting a signal, I don't think it's well known because no one has really tested it.  The towers have been tested and are designed for terrestrial use, and the conditions are much different (besides the lack of objects such as hills, trees, and buildings, there is the excessive speed at which you're moving in an airplane, which would make it very difficult if not impossible for your call to be transfered from one tower to another, which would explain why the pilot above said the calls get dropped quickly).
623115
I believe in cell phones.\n\nI believe that if I receive a call from you it's not the phone that I'm talking to, but to a person that is not even inside the phone.\n\nI believe that when it runs out of battery, even in the middle of a conversation with you, that doesn't mean you've disappeared from the universe.\n\nI believe that every telephone was designed to receive a unique number through a unique frequency, and that such number and frequency are there even when the telephone is not in use.\n\nI believe that all cell phone signals are everywhere (within the range of the antenna)\n\nI believe these signals can be received by every single telephone in the area, and that it is even possible that any of those signals could interfere with any telephone conversation.\n\nI believe this because I can understand it.\n\nJust try to explain it to someone who hasn't heard a word about electricity.\n\nAnd try to convince them it's not something evil just because they don't understand it.
999484
No, my job does not, but I totally know what you mean. Cell phones are great for most people - but have you ever been in an airport and watched those poor businessmen? They are like making deals while standing in line! Travel was probably their one escape from work during the pre-cell era. Now that is gone. How sad.
1050539
This will depend a great deal on your cell phone. Some phones have you pull rings only from websites browsed by your phone or have you email tones to an inbox that only your cellphone can read or you may have to connect a data cable and use software provided by your cell phone company.
774184
A very good, complicated and interesting question.  Katy brought up a good point.  You could write entire book on how cell phones has changed daily life around the world.  Just think of how many business decisions are now done in real time rather than getting to a land line (telephone.)  Or how about a reporter in the field giving a story before he or she has set up the equipment to broadcast the story?  Or how about the reporting of the Iraq war where no broadcasting equipment was even available?  With cell phones, many of which now have cameras built into them, people are taking pictures of crimes as they occur.   This is also true for reporting crimes in areas that didn’t normally have phone access.\n\nSince you didn’t speak of which wireless technology you were referring to I can only assume you are talking about all wireless technology so I will discuss some others here.\n\nIn the last few years wireless networking for home computing has really taken off.  It has become much more affordable and easier to configure for the average person.  Now here is where it gets interesting.   Many new laptops have the ability for you to use a wireless networking adapter in them or with them.  Some cities, including mine in Anaheim California, are going to make the whole city wireless!   They are going to install wireless Internet transmitters all over Anaheim so everyone has a wireless connection to the Internet.  Even people visiting from out of town can use the wireless system but they have to pay a small access fee.   Can you imagine driving across the county someday and being able to access the Internet right from your car?\n\n\nLet us not forget that the first wireless technology started with the radio.  Man discovered radio in the late 1800’s.  Radio technology grew in bits and pieces but by the turn of the century wireless communications had been established.  All wireless routers and wireless Internet communication uses radio waves to send the data.\n\n\nLet us not forget RADAR.  RADAR is an acronym for Radio Detection and Ranging\nand helped us win the world war II.  One of the first uses of Microwave technology was used in RADAR in the world war II also.  Most households now use Microwaves to cook food with so radio waves also help us heat things\n\n\nWhat about television transmission?  Isn’t that also wireless?  Although many people now use cable (because they have paid for premium channels) television is a wireless technology.\n\nAnd others:\n\nRadio transponders to find lost aircraft (also a transponder)\nLo Jack stolen automobile retrieval device (also a transponder)\nNavigation\n\nRadio Frequency Identification (RFID) (also a transponder)\nRadio Frequency Identification is a way to remotely receive data from RFID tags or transponders.  They are used on toll roads and even at Mc Donald’s to buy lunch with a swipe of a small device.  They are used soo much that this needs to be researched all by itself.\n\nWhat all wireless technologies have in common is that they are all based on Radio waves.  All of things that I have mentioned are based on Radio technology \n\n\nP.S.  I usually don’t cut and paste and if I do I will say that, that is what I am doing and explain where that information came from.  I like to read information from multiple information sources then put that information together in my own words while keeping the article technically and factually correct.  And as always, I will point to web sites or other information to prove that my information is factual.
534759
Satellites. For cell phones, a radio signal is sent to a tower and then to a satellite and back down and to the other phone. For GPS, a signal is sent directly and so the user's location is more exact. For remote controls, the remote sends a signal to the object through the thing on the top and that is received by the sensor on the object.