Mobile phones

Mobile phones

The reason for the emergence of all sorts of conjectures and inventions is elementary ignorance. Indeed, not many of us, even today, can boast that we are fully familiar with the principles of cellular networks, as well as with the peculiarities of the functioning of our own mobile phone.

The communication range in the GSM standard can reach hundreds of kilometers. The maximum possible communication range in a standard GSM network is no more than 35 km. Some GSM operators at base stations located on the seashore include a special mode, thanks to which communication is possible at a distance of up to 70 km. Often on the seashore or in the mountains, you can find new GSM networks when searching for a network, but you cannot register with them due to the distance. There are no distance limits in the NMT, CDMA, AMPS mobile communication standards. That is, communication is possible as far as the telephone "finishes" and other conditions allow. With the use of external antennas and with a successful combination of circumstances, communication can be established at a distance of up to 100 km. (For example, for NMT or DAMPS)

Within the limits of the radio coverage area indicated on the map, a cell phone must function absolutely everywhere. In reality, subscribers have to face situations when the phone "stalls" and within the zone of confident reception! But such are the features of the propagation of radio waves: in an inhomogeneous space, they cannot create an electromagnetic field with a uniform intensity! Hence the appearance of "white spots" on the radio coverage map, the so-called "radio shadow zones". As a rule, this is a problem of the first stages of the development of a cellular network or its fragment. Subsequently, the operators seek to equalize (as far as possible) the coverage area by increasing the number of base radio stations serving this territory. But this does not solve the problem completely and irrevocably! Within the zone of reliable reception, there are two "sub-zones": an outdoor zone, so to speak, "in the fresh air", and an indoor (or transport) zone. If with the first everything is more or less clear, then with the second it is a real trouble! Buildings are brick, reinforced concrete, wooden and even metal (hangars, warehouses). And in all cases, the conditions for the penetration of radio waves into buildings are different: in some, the waves penetrate with insignificant attenuation, in others, the attenuation is more intense, and in the third, the penetration of radio waves is generally impossible from the point of view of physics (metal hangars and warehouses, safe rooms and bank vaults ).

The location of the owner of the GSM phone can be tracked down to a meter. In a standard GSM network, it is realistic to find out the cell in which the phone is located and the distance to it (not more precisely 540 meters), which gives accuracy, in the center of a large city 500-4000 square meters, on the outskirts of 2-25 square kilometers. This data can be seen even on the screen of NOKIA phones in NETMONITOR mode. To improve the accuracy of coordinates determination, the operator needs to install additional expensive equipment. In this case, the accuracy of the determination increases to a section of 50x50 meters. Abroad, in some countries, similar services are provided to everyone, for example, to find a car or monitor the location of a child.

A stolen mobile phone can permanently stop working after some time. Indeed, any GSM network includes an EIR (Equipment Identification Register) device. This device has several lists. If the serial number of your phone is included in the "black" list, the network will not give permission for its operation. It often happens that a telephone operating in the CIS countries, when traveling abroad, refuses to register in the network, which means that it is simply included in the "black" list in this country. There are no computer databases of stolen phones. That is, it is impossible to check the phone for hijacking. The serial number of the phone is "wired" inside the phone and is transmitted by the phone at every call for recognition by the network. Can this electronic number inside the phone be changed by a hacker method? Answer: Yes, but not for all models. Currently, specialists from all phone manufacturers are working to eliminate this possibility.

GSM conversations can be listened to at the amateur level. This myth is also not true. Let's start with the fact that information is transmitted digitally. If you tune the receiver to GSM frequencies, you will only hear crackling and squeaking. This is how a digital signal "sounds". In addition, this section uses special encryption algorithms, for example A5.2, A8. This algorithm is difficult to describe at the user level, speech is not only transmitted, but also encoded. Most networks use the Frequency Hopping function, its essence is that the mobile phone jumps between several frequencies at a speed of 217 times per minute, which makes listening even more difficult. When you move around the city, your phone "jumps" from cell to cell, which additionally complicates tracking your conversation.

To replenish the deposit in pripaid cards (for example Beeplus), a 14-20-digit code is used. It is possible to pick up or generate a fake code to replenish the deposit. This is not true. Purely mathematically, combinations of 14-20 digits give many options. The operator's full numbers are generated by the random number method. And they have no regularity. Guessing the number - the probability is negligible.

It is possible to remake the phone or reprogram the SIM card to use the GSM phone for free. These rumors come from the United States. The basic US standard AMPS does, with some trickery, allow you to do this sort of thing. By some estimates, up to 10 percent of phones operating in the United States are illegal. With huge traffic volumes, America's mobile operators don't see this as a major problem. Moreover, such phones do not "live" long. In the GSM standard, such things are not yet possible.

The myth of the phone rework. Calculation of the number and duration of calls does not take place in the phone or in the SIM-card, as many believe, but in the GSM switch (except for pre-paid cards of the same type). The cost of calls is calculated by the billing system, which takes data from the switch. There is no way a mobile phone can get the switch to stop monitoring calls.

The cloning myth (making a copy of a SIM card). The SIM card contains various information, such as PIN code, PUK code, subscriber's address book. But there is also service information inaccessible to the user. The basis of SIM card security is the Ki code. This code is stored in the card and at the operator. Based on this code, tricky processes of authentication (authentication) of the subscriber take place, according to the A3 algorithm. It is impossible for a simple user to pick up or read this code. The code is stored in a non-readable area of ​​the SIM card. In addition to this code, you need to know the IMSI (identification code) of the card, this code is open. A year ago, a group of Western programmers managed to read the code data and simulate a SIM card with a computer program. It took them about 6 hours of work with someone else's card to read the Ki code. They failed to create a clone (copy) of the SIM card. Thus, the standard developed in the 70s still provides reliable protection.

Phones that have been decoded do not work well, and over time they can completely fail. If the phone has been decoded, you lose warranty service in service centers, and the manufacturer is not responsible for the quality of the phone. At the same time, as the phone works after decoding, it will work in the future, and nothing terrible should happen. Sometimes after incorrect decoding some menu items are missing in the phone, the phone parameters deteriorate, some functions do not work correctly, this is rare.

If you add a newer software version to your phone, it will work better. Changing the phone's firmware is like changing the operating system on a computer. The manufacturer, creating a model of the phone, has also created software for it. Over time, small problems can be found in the phone, they can be called "glitches". For example, at some point in the menu, your phone "freezes". A newer, more recent firmware version eliminates these shortcomings. Sometimes the latest firmware contains new languages, for example, Russian. Ericsson T10 is often "poured" with firmware from Ericsson T18, and voice dialing appears in the phone. The firmware does not usually affect the reception parameters. If your phone often freezes or turns off, the firmware can be changed. If it works normally, you should not, for example, upgrade the phone software because of one new melody. Anything can happen.

A mobile phone is harmful to health. A mobile phone as a transmitting device emits radio waves at a frequency of about 900 megahertz. The maximum power of a portable telephone varies from 1 to 2 watts for different models. But GSM phones do not emit this power all the time. Approximately every 4-6 seconds (depending on network settings) the phone changes the power output. And he tries to keep it as minimal as necessary for communication. This feature saves your battery, protects your health and improves overall network quality. You've probably heard a lot of interference from your phone, such as speakers or radio. Make a call and you will notice how the interference will gradually disappear within 10 seconds. Here's a simple proof of power adjustment. Naturally, 20 milliwatts is much less harmful than 2 watts. In older standards of cellular communication, such a function did not exist, and there is no such function in powerful radio extension cords.

Cell phones cause cancer. A study published by the Royal Scientific Society of Canada concludes that talking on a cell phone cannot cause cancer or other illnesses. A group of eight scientists reviewed numerous studies related to the safety of using cell phones and found no evidence for the emergence of diseases associated with exposure to radio waves. The scientists found that the evidence "does not support the conclusion that exposure to radio frequency fields of the type and intensity produced by radio communication devices promotes the appearance or development of tumors in animals or humans." The British Independent Expert Group's report on mobile phones also found it unlikely that mobile phones could cause cancer or any other disease.

Mobile phones interfere with the operation of the pacemaker. More than 1 million people in the world live with implanted pacemakers. In cases where the heart's own rhythm is intermittent or too weak, this device sends out the electrical impulses necessary for the normal functioning of the heart. German scientists studied whether a cell phone could cause a heart pacemaker to malfunction. Three cellular standards were tested: C-net (NMT 450), D-net (GSM 900) and E-net (GSM 1800). In the experiments, 231 pacemakers from various manufacturers were tested. The results are as follows: 31% of stimulants experienced interference from C-net phones and 34% from D-net phones. When using telephones operating in the E-net standard, there were no failures in the operation of pacemakers. Despite the above data, it is not recommended to carry a mobile phone near a pacemaker, all the more you should not bring a terminal operating in an active mode (i.e. during a conversation) to this device. However, this, as well as the fact that the phone must be turned off when entering medical institutions, is said in the instructions for any mobile terminal.

Mobile phones cause explosions at gas stations. The danger is associated with the possibility of an explosion, which can occur as a result of a failure in the operation of the electronic equipment of a gas station under the influence of the magnetic field of a cell phone, as well as an explosion of gasoline vapors from a possible spark if the device falls to the ground. The reason for concern was an explosion at an Esso gas station in Malaysia. Necessary clarification: a direct link between the disaster and the use of mobile phones has not yet been proven. At the time of the explosion, many people who were on the territory of the gas station spoke precisely on them. Since no other explanation for the explosion was found, the management of most gas stations decided to take precautions and banned the use of mobile phones on their territory.

Mobile phones interfere with aircraft navigation equipment. According to research conducted by aircraft manufacturers Boeing and Airbus, the ban on the use of mobile phones on aircraft has no scientific basis. The same conclusion was reached by representatives of the American and British civil aviation services. Research by Boeing has shown that 20 mobile phones in the Boeing 737 cabin do not cause any interference. Airbus conducted similar research. Analysis of 70,000 aircraft crew reports did not reveal a single case of interference with the use of mobile phones. Despite this, no airline in the world allows the use of a cell phone on board their liners.

Watch the video: old mobile phones second hand mobile best price and good condition (November 2021).