GSM SIGNALS Consider the major distinguishing characteristics of GSM systems. 1. By price GSM pagers could be divided into the "cheap" and "expensive". As a rule, "cheap" GSM systems consist of a control unit and a mobile phone (usually bought myself) patterns, which supported it. In "expensive" phone system is not used, because GSM module slot for the SIM card and antenna are part of the control unit. And even more "expensive" - used GPS receiver (road option) to obtain location coordinates. 2. By way of warning alarm GSM pagers are : warning SMS; Callers; Referring callers and SMS. An important figure in this performance is free, putting them on alert, because most callers warning devices operation is performed only after the subscriber (the owner) picked up the phone and heard a voicemail. In this case, there is a connection and it is necessary to pay mobile network. Just another case where the importance piece zone is the length of GSM call a pager and you do not need to raise the tube to see what zone worked. But you do not apply because the you know, I opened a door, window, hood or trunk. 3. According to the method of programming GSM pagers into programmable SMS messages and programmed DTMF signals (tone), and government-controlled method calls, SMS messages and DTMF signals. Undoubtedly, programming and management DTMF- signals convenient, reliable and fast, although money (as a connection). The devices have this feature can be attributed to the "expensive". Not the case with SMS device management, cheap, but unreliable. Most free version of a device operated on call. In this case, the device takes toll as a team, and after the gun. But the call can be managed only two operations : establishment of a / de-protection. Another type of management GSM pager is typical query (operator services), but it is only used in operations verification and updating accounts (cash balance), and mainly in devices with integrated GSM module. An important point in the programming GSM pager is opoveschaemyh record numbers (the phone number of owner, his relatives or guards) to the device. In most devices, these numbers are stored in special cells in the SIM card and recorded there in the editing mode address book. It is not very easy, because in the case of loss or theft of phone you temporarily unable to manage the facility, and during this time can be a lot (of robbery or theft). This is not you fear if the number or list of numbers is a cellular-volatile memory devices. In such a case, manage GSM pager you can with any other means of a mobile phone SMS commands code. 4. According to the method of power GSM pagers are : eating only 220 of the network or from the battery 12 (car); Eating as a network or avtoakkumulyatora and its internal battery (with a major power). When than last, when a power failure can occur owner warning bell or SMS message. Typically, it is "cheap" device consisting of a control unit and a mobile phone. It is the internal phone battery they eat. Most of the same "expensive" system (no GSM module) support the battery is more options and bought separately. The importance of the support of the electric power source (additional battery) talk too. 5. Also GSM system can be divided on the existence of additional functions : connect GPS receiver; Listen to the situation inside the facility; Transfer photos or video; Management of external elektroustroystvami; "Glushilok protection." 5.1. The function of connecting the GPS receiver is suitable only for movable objects (passenger and freight). But it will be worthless if you are not connected to any security service or not a subscriber to any information retrieval system. These systems can not only identify the location (most often visually) of the units, receive a photo or video information from the site / sites, but also to remotely manage their condition. An integral part of such a system is a software product (medium), which provides online tracking of all subscriber services. These systems are costly and are mainly used to monitor traffic, taxis and professional services. Some manufacturers of GSM pagers are not an opportunity to connect GPS receiver, referring to the fact that some mobile network operators has been met by almost 100% and they are positioning subscriber services LBS (Local Based Service). But that was not the case! First, I do not know what percentage of land covered with Russia, but 100% e-cover the territory of Ukraine will still be some time, holes in the coverage shortage. Secondly, guaranteed accuracy LBS services is low, because depending on the zone coverage sector base station and is in the range of 500 meters (radial width segment) to a few kilometers. Precarious accuracy can be less than 500 metres, but this is will depend on where the site is : in the city (high density of base stations) or in the countryside. Information provided by the subscriber is a graphical display on a map the location of the ground segment. 5.2. Feature watch the situation inside the facility exists in virtually all GSM systems and is not paid for more options. A very useful feature, especially in situations where the alarm was needed, and I am 100% confident in hacking. The only difference this function on different devices is how it escalates. In some systems, the owner shall send SMS command to activate. And then the owner or device back to picked up the phone and listened, or owner must call on the device.