Cellphone Spy listening devices phone Principle

The principle is the GSM channel to voice signals in the system, channel coding, encryption, interleaving, burst formation by modulated burst firing. In the mobile phone receiver, the signal demodulated by the de-interlacing, channel decoding, voice decoding, and then restore the user's mobile phone into a voice signal. GSM system used in the transmission band time division multiple access (TDMA) technology, in which each carrier frequency channel bandwidth is 200KHz, 8 time slots per frame, in theory, allow a radio call at the same time 8 groups, each time slot Length of 0.577ms, the frame duration 4.615ms, is to split into cyclical time frames, each frame and then divided into many a time slot, after the time slot allocation based on specific principles, allows mobile phone users in each frame by Specified time slot, toward the base station sends a signal, the base station in their respective space in the specified time, receives a different signal of mobile phone users, while base stations are also required time gap, different mobile phone users to transmit signals, each mobile Users in the specified time slot in the received signal, so there is no guarantee, in the same channel without interference between users can be, this is the individual mobile users in the use of mobile phone, occasionally hear from others in the microphone Talk reason to consult on this issue when the operators, they are not saying, of course, on the phone on which part of the Spy listening devices is listening on the implementation, they would never say.
with the GPS in most cities satellite map, objects can be monitored to monitor the specific location to search.

Ordinary mobile phone into the listener: active and passive Spy listening

(1) active listener, it can capture all the information by monitoring mobile phones, and can be monitored and theft as a calling or called numbers, in short, may exercise all the functions of the phone being monitored. It can be seen, active listener great harm may be only the official hold of this technology.
(2) passive listeners, the so-called "listening king" Such is the passive listener, listening distance limitations due to the actual little use, so even if the public security organs do not use this equipment, they need to listen when they were authorized in the Procuratorate, the commission to carry out the telecommunications sector, of course, this is the law.
Passive listener, the actual communications company proficient in communication networks of professional and technical personnel, basically you can assemble, in addition to almost nothing outside of the computer hardware costs. There have to admire the professional quality of those employees, or mobile phone really will be flying the listener, the reason doctors know that certain drugs like mixed use, will be the consequences of the truth, but they are not out of professional ethics will just go and talk about the same, of course, does not rule out the possibility that they just afraid of losing their iron rice bowls. Active listener and the listener has a total of passive resistance, that is, start listening device, must be monitored in the same mobile phone base stations within the same, which means that they are limited by distance, not exaggerated, as some people that can be carried out without distance limitations telephone surveillance, and monitoring the start of CDMA in a few seconds behind the listener. Those who can block, said hundreds of kilometers, without distance limitations of passive listeners, is nonsense, unless the country has only one base station. Those who believe, as long as the company's technical staff to find a communication, ask to know how ridiculous these statements, the listener can only ordinary mobile phone and base station use.
In short, said the passive long-distance phone listener can listen in my range of knowledge and ability that is impossible, if it can, there is a possibility of bird, who can only be sold within the technology and telecommunications sectors colluding, staff within the department through the implementation of telecommunications monitoring, but I think no one would dare to do so.

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Created on Dec 31st 1969 18:00. Viewed 0 times.

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