DIY usb modem repair

Typically, in the elementary school curriculum, children are taught to first find the root of a word. However, this approach is incorrect, as it leads to possible errors in the search for morphemes in a word. The sequence of actions should be as follows:

1. Determine the part of speech to which the word belongs. It is important to do this right away. For example, if the token is immutable, there will be no ending. Also, do not be lazy to remember the features of the formation of this type of tokens.

2. Next, find the ending. To do this, you need to select the maximum number of options with different endings, and then graphically highlight the ending.

3. Mark the existing suffixes and postfixes, which are always preceded by the ending. Do not forget that the same parts of speech are often formed according to the same model and have the same formative suffixes, of which there can be more than two.

4. If you have followed the two previous steps correctly, then determining the stem of a word will not be difficult. Select the base graphically, highlighting all the word except the ending, since this mass is not included in the base.

5. Designate graphically the prefix (prefixes) of the lexeme. For the purpose of self-control, try to choose several variants of tokens of the same part of speech with the same prefixes.

6. The last stage is the selection of the root of the word. Note that complex tokens can have two roots. In this case, do not forget to graphically indicate the connecting vowel.

For a person who does not sit still and cannot do without the Internet on his laptop, a CDMA modem is a necessary device in the user's arsenal. Usually, such modems have a USB interface, which is very convenient for use, but during operation, due to negligence, it is usually the USB plug that breaks down and it becomes necessary to repair the modem.

Repairing such a malfunction requires some "creative" approach to insert the plug back into the modem, see an example of such a repair in the pictures below. If the damage is not severe, then you can align and leave the original plug, but it is better to put a new one, which is certainly more reliable.

The article is out of date. We no longer repair 3G USB modems.

The second common problem is wear and tear on the moving parts of USB modems. Usually, the wires or ribbon that connects the plug to the device board are frayed. An example of such a malfunction and how to fix it can be seen in the pictures below.

Another type of malfunction is damage to the SIM card receiver when contacts or the entire SIM slot are broken. In this case, it is necessary to replace the sim-receiver, choosing the appropriate size and contact group.

The modem loses connection or gives out a weak network signal if the input circuits and the modem antenna are faulty, in which case it may be necessary to replace the signal amplification chip or repair the device antenna.

Unlocking the modem from the operator is necessary if you want to use the purchased modem with a sim-card of another telecom operator, which for one reason or another is more convenient for you.

Nowadays, the 3g network has become widespread, so many cellular companies produce USB modems for it, or rather, they take a well-known manufacturer, stamp a logo on the case, and install their software. Recently I got a couple of such representatives, it seems like they are not workers, but I decided to spin it up, see what's what and, if possible, restore and unlock it.

The first device was from the famous yellow striped brand Beeline.The modem was very common once, it can be safely used now, a couple of minutes with the instrument and we see the filling of the whistle device - the modem was clearly drowned in something sweet, such as tea - after cleaning a little and testing it, I understand that there is absolutely no way to revive it, since it does not respond to commands at all and is not detected by the port in any way, it seems that the controller responsible for the usb port has died and the treatment of such a patient becomes unprofitable.

Although you can see a photo of the insides - it may come in handy during disassembly and assembly so that everything is done in detail.

The next device turned out to be a modem from the also very famous operator Megafon, then I had to sweat to unscrew the screws - too narrow non-standard edges turned out to be.

Having disassembled and cleaned (judging by the oxides, just rain-type water got in) and heated a couple of straps, cleaned the connectors with a solvent, and then managed to start the whistle with alcohol!

The antenna, judging by the size, is larger here, and it sits firmly - besides, this device can be easily sewn and unlocked with simple manipulations, so a lot of interesting things can be done with the worker in software.

The LED in the smd case turned out to be very bright and clear, the device works quite clearly.

At the moment when I wrote comments on the articles of the Mozhochin, I literally lost the Internet in mid-sentence. First of all, I went to look at the modem, where I found out that it was finished - not a single LED was on. After thinking a little, it was decided that there was nothing to lose (the guarantee was over long ago), and the autopsy no longer scares me.

This article is more of a success than a natural victory over a breakdown, but still. I am a person a little distant from delicate electronics, but I can distinguish a burnt look. Therefore, having disassembled this device

the following picture was presented to the light white:

After careful sniffing and inspection, the gaze settled on this condenser.

Its shape changed markedly, although there was no gap. The marking informs that its capacity is 3300μF and voltage is 16V. Since I don't have an LC meter, I continued examining it with a multimeter and measuring its resistance. So it interested me. The charge was taken very reluctantly, and the increase in resistance quickly stopped.

After that, two Soviet capacitors, with a total capacity of almost half of the original, were pulled out of some frames.

After connecting one capacitor in parallel, the power LED showed signs of life, which meant the correct course of my thoughts. Having soldered the second one, I tried to turn on the modem - and, lo and behold, the Internet started working! Therefore, I can write this article!

Now it remains to spend $ 0.5 to buy the original capacitor, and 10 minutes of time to assemble everything in a bunch! Of course, this is not a detailed analysis of the modem repair, but still a description of one of its breakdowns. So if someone comes in handy - I'll be glad! :)

After purchasing a powerful soldering iron, I decided to continue the repair. Armed with a new unit, I still managed to pull out this evil condenser.

In its place, a capacitor found at work, although inferior in capacity, was hoisted.

After that, the modem blinked merrily with LEDs.

And he briskly sent a bunch of information packets through the wires. :)

• We fill the niche part 3 or make a chest of drawers out of garbage with our own hands - 12/20/2014
• Filling a niche part 2 or making corner shelves with our own hands from garbage - 12/19/2014
• Filling a niche part 1 or making shelves with our own hands from garbage - 12/19/2014
• The idea of ​​decorating a repaired wire with your own hands - 09/30/2014
• DIY plywood box - 09/22/2014
• Do-it-yourself drawing on T-shirts - 09/15/2014
• Do-it-yourself sealed container for welding electrodes - 09/02/2014
• DIY assembly on dowels or thorns - 07/27/2014
• Cabinet and shelves as an idea for filling a niche - 07/25/2014
• Do-it-yourself folding table-cabinet - 07/15/2014
• Making a universal playing board with our own hands - 07/05/2014
• We clean jeans from spilled PF-115 paint with our own hands - 07/01/2014
• Do-it-yourself Eurobook sofa cover - 01/07/2014
• Convenient case for a multimeter with your own hands - 12/26/2013
• DIY winter mask - 12/20/2013

It is important to add that when installing the Conder it does not overheat it, and also does not confuse the polarity (if you confuse it, when you turn it on, there will be "pshshshshsh" and swelling of the freshly soldered Conder).

Absolutely fair! Pay attention to the color coding. In general, I try to take pictures first. Well, and the popovod of overheating, you also need to be careful.

why is the quality of photos so bad

Because they were done in poor lighting. And everything is clear to such pictures, so I see no reason for indignation.

And also due to the fact that the camera was not at hand, and the only thing that was at hand was the phone and that Samsung bought for work.

Dried or swollen electrolytes sometimes drag other parts on the boards with them. So replacing capacitors doesn't always help.

Comrades! Thank you for your help! Based on your advice, I still managed to bring my modem to a human form, and finish writing an article!

This is a solder with a high content of lead, if you do not have a powerful soldering iron at hand, then I use a turbo lighter

Usually - take a more powerful soldering iron.

I got a new soldering iron today. Let's see what happens!

Guys! Guard! I can’t evaporate this ill-fated capacitor! Help with advice! I warm him - but he is not in any! I already coated it with solder so that the heat transfer was better, and still does not want to! What do you do?

Sorry for my "correctness", I just want to earn M $

Everything is fine! We must strive for excellence! :)

And also in the sentence "After which two Soviet capacitors were pulled out of some frames, with a TOTAL capacity of almost half of the original" there is an error in the word SUMMARY.

In the sentence "After the PARALLEL connection of one capacitor, the power LED applied to the PICTURES of life" there are errors in the words PARALLEL and SIGNS!

good day, 70% of all computer breakdowns (motherboards, power supplies and video cards) that I encountered were just such a breakdown, drying out or swelling of an electrolytic capacitor, it happens that the kander did not swell and there is a sticky puddle on the board where it is soldered or the appearance of a fat spot is also a factor in the failure of the latter, and I rarely use the LC_meter, basically I check them in the same way as the author, I solder them and alternately change the polarity of the instrument probes with a multimeter,

Cool) Mozgochin will not be left without an Internet or even electricity. There is always a way)

P.S. 70% is a lot. You can open a workshop knowing this

Your browser doesn’t support canvas.

• 
• 
• 
• 
• 
• 
• 

The story is this:
A friend was sitting on the Internet at night, staying up a bit and fell asleep. Naturally, without thinking for a long time, he took the laptop and fell in order to wake up its owner. The laptop did not become anything from the fall, since this very fall was softened by our modem. It’s a pity I didn’t see what the USB connector had become, but from the words and fingers it was possible to understand what was the cause of the breakdown. An autopsy confirmed that as a result of a fall from a height of “half a foot”, the connector was bent so that the contacts inside it broke. In order not to torment you with fabulous words, I will give a series of photos of the stages of repairing the modem, sometimes words of description will be encountered)

Photo # 1
The first thing I saw after the autopsy was a broken, creepy sight (well, maybe not so creepy))

Photo # 2
Here I compare my own broken connector and the one bought at the radio outlet of the local market for 2,500 thousand Belarusian rubles.

Photo # 3
This photo shows what I mean by the word extraction)
ZY It was difficult to unsolder the fastening ears, advice is to pull out)

Photo # 4
Well, here is the conclusion of today's article, it is better to solder something yourself, it will come out the same as if you give it for repair, and it will cost less)

The modem is fully operational, but still there were fears during installation to damage any elements of the board, since a couple of layers are still there)
Good luck!!

Replacing the USB connector on the BEEELINE modem.

The book deals with practical issues related to the repair of personal computers at home or office.

After reading it, you will learn about methods for eliminating common computer malfunctions, learn how to check its performance, identify devices that have failed, and select a suitable replacement for them. The pages of this publication provide recommendations on how to prevent problems and keep your computer running. The material is presented in a simple and intelligible form, so even a novice user will be able to understand it.

The main malfunctions of modems

The modem's input circuits can be damaged by lightning storms if it is connected to a telephone line. Therefore, in a thunderstorm, it is required not only to turn off the PC, but also ALWAYS disconnect the modem from the telephone line.

When starting to repair a modem, first of all, you need to visually inspect it. Malfunctions after a thunderstorm are often immediately visible. Look at the pull-up resistor and ICs. Cracks and chips may be visible on them.

After visual inspection, turn on the power. Check if the LEDs are on. Connect the modem to the telephone line.

Immediately after connecting, the modem should not "occupy" the line. Call your landline phone number, for example, from a mobile phone.

If the line is busy, it means that the modem is "seizing" the line. If there is no “busy” signal, the loop is not closed and is in its original - good condition. If the modem occupies the line, then you should check the key or relay, or protective elements, diode bridge.

Then check if the modem picks up the phone after the command. Try using the Hyper Terminal program (available in Windows) and issue the ATH1 command to pick up the handset. Make sure your modem has completed it.

After the ATH0 command, the modem should hang up. If the modem does not "pick up" the phone, you should check the resistor, relay, diode bridge, protective elements, key transistor, zener diode.

If the AT commands do not work, then the port chip may be replaced.

If the line supports tone dialing, you can issue the ATDTxxxxx command, or ATDPxxxxx for pulse dialing, where xxxxx is the phone number.

If the modem reported - No Dial Tone, check the zener diode, transistors, if everything is checked and correct, then the microcircuit may be out of order.

If the transformer is out of order, the load resistor - low-impedance resistance - 5-20 Ohm could fail along with it. The contacts of the reed relay may also fail, and the optoelectronic relay has an internal field-effect transistor.

In addition, a zener diode may turn out to be faulty, which can be changed to any one with a stabilization voltage of about 9 V.

A USB modem ZTE MF627 has arrived for repair

with a declared malfunction - not installed. We are trying to install:

Installation takes about a quarter, after which a message appears:

Datadata2.cab The volume for the open file has been modified externally, so this file cannot be accessed.

Well, I will describe the sequence of steps for recovery:

1. Download this file. It contains - firmware for MTS, drivers for USB modem and installation archive of MTS Connect Manager.

2. Install MTS Connect Manager from the archive.

3. Install drivers for ZTE WCDMA Technologies MSN.

4. Then run the firmware file and press the "Download" button (if it is not active, then not all drivers are installed - everything is in the archive, try to install others).

5. The firmware has started. After completion (my firmware took 11 minutes), the following window should be displayed:

6. Remove MTS Connect Manager (remember to remove the modem from USB beforehand). Then we plug in the modem and try to install MTS Connect Manager from the disk located in the USB modem. Installation proceeds fine, no error windows appear. At the end of the installation, the following window is displayed:

All devices in the system are normal:

All photos were taken with a Kodak EasyShare C1530 camera.

By the way, to get unlimited Internet for a USB modem, Megasimka is best suited - an automated online store for SIM cards and tariffs. It has a large selection of SIM cards from various operators and tariffs. Choose what suits you best and use your USB modem. It was always interesting to try to open your own online store, albeit not fully automated, but all the hands do not reach the point of installing a plug-in for a wordpress or just some script of an online store. I would like to create a store of components for electronic equipment - to sell transistors, resistors, capacitors, microcircuits. I just analyze the prices for spare parts in my hometown and I am horrified - the prices differ from the prices for aliexpress at least three times, and for individual items up to 20-30 times. It's just over the top of the profit. I understand that money is invested in a product and is dead weight if no one buys this product. But not 30 times. A spare part worth 1 ruble to sell for 30? This is super profit in its purest form. As an option, I want to try to trade fitness bracelets, it seems to me that this is a very relevant topic now. I have to do it, but with this I, as always, have problems - there are many words - few things to do. Okay, I’m distracted for some reason. Bye everyone! Until next time on the site!

• 

Is your TV, radio, mobile phone or kettle broken? And you want to create a new topic about this in this forum?

First of all, think about this: imagine that your father / son / brother has an appendicitis pain and you know from the symptoms that it is just appendicitis, but there is no experience of cutting it out, as well as the tool. And you turn on your computer, access the Internet on a medical site with the question: "Help to cut out appendicitis." Do you understand the absurdity of the whole situation? Even if they answer you, it is worth considering factors such as the patient's diabetes, allergies to anesthesia and other medical nuances. I think no one does this in real life and will risk trusting the life of their loved ones with advice from the Internet.

The same is in the repair of radio equipment, although of course these are all the material benefits of modern civilization and in case of unsuccessful repairs, you can always buy a new LCD TV, cell phone, iPAD or computer. And for the repair of such equipment, at least it is necessary to have the appropriate measuring (oscilloscope, multimeter, generator, etc.) and soldering equipment (hairdryer, SMD-hot tweezers, etc.), a schematic diagram, not to mention the necessary knowledge and repair experience.

Let's consider the situation if you are a beginner / advanced radio amateur who solders all sorts of electronic gizmos and has some of the necessary tools. You create an appropriate thread on the repair forum with a short description of “patient symptoms”, ie. for example “Samsung LE40R81B TV does not turn on”. So what? Yes, there can be a lot of reasons for not switching on - from malfunctions in the power system, problems with the processor or flashing firmware in the EEPROM memory.
More advanced users can find the blackened element on the board and attach a photo to the post. However, keep in mind that you replace this radio element with the same one - it is not a fact that your equipment will work. As a rule, something caused the combustion of this element and it could “pull” a couple of other elements along with it, not to mention the fact that it is quite difficult for a non-professional to find a burned-out m / s. Plus, in modern equipment, SMD radio elements are almost universally used, soldering which with an ESPN-40 soldering iron or a Chinese 60-Watt soldering iron you risk overheating the board, peeling tracks, etc. The subsequent restoration of which will be very, very problematic.

The purpose of this post is not any PR of repair shops, but I want to convey to you that sometimes self-repair can be more expensive than taking it to a professional workshop.Although, of course, this is your money and what is better or more risky is up to you.

If you nevertheless decide that you are able to independently repair the radio equipment, then when creating a post, be sure to indicate the full name of the device, modification, year of manufacture, country of origin and other detailed information. If there is a diagram, then attach it to the post or give a link to the source. Write down how long the symptoms have been manifesting, whether there were surges in the supply voltage network, whether there was a repair before that, what was done, what was checked, voltage measurements, oscillograms, etc. From a photo of a motherboard, as a rule, there is little sense, from a photo of a motherboard taken on a mobile phone there is no sense at all. Telepaths live in other forums.
Before creating a post, be sure to use the search on the forum and on the Internet. Read the relevant topics in the subsections, perhaps your problem is typical and has already been discussed. Be sure to read the article Repair strategy

The format of your post should be as follows:

Topics with the title “Help fix the Sony TV” with the content “broken” and a couple of blurred photos of the unscrewed back cover, taken with the 7th iPhone, at night, with a resolution of 8000x6000 pixels are immediately deleted. The more information you post about the breakdown, the more chances you will get a competent answer. Understand that the forum is a system of gratuitous mutual assistance in solving problems and if you are dismissive of writing your post and do not follow the above tips, then the answers to it will be appropriate, if anyone wants to answer at all. Also keep in mind that no one should answer instantly or during, say, a day, no need to write after 2 hours “That no one can help”, etc. In this case, the topic will be deleted immediately.
You should make every effort to find a breakdown on your own before you get stumped and decide to go to the forum. If you outline the entire process of finding a breakdown in your topic, then the chance of getting help from a highly qualified specialist will be very great.

If you decide to take your broken equipment to the nearest workshop, but do not know where, then perhaps our online cartographic service will help you: workshops on the map (on the left, press all buttons except “Workshops”). You can leave and view user reviews for workshops.

For repairmen and workshops: you can add your services to the map. Find your object on the map from the satellite and click on it with the left mouse button. In the field “Object type:” do not forget to change to “Equipment repair”. Adding is absolutely free! All objects are checked and moderated. A discussion of the service is here.

The book deals with practical issues related to the repair of personal computers at home or office.

After reading it, you will learn about methods for eliminating common computer malfunctions, learn how to check its performance, identify devices that have failed, and select a suitable replacement for them. The pages of this publication provide recommendations on how to prevent problems and keep your computer running. The material is presented in a simple and intelligible form, so even a novice user will be able to understand it.

The main malfunctions of modems

The modem's input circuits can be damaged by lightning storms if it is connected to a telephone line. Therefore, in a thunderstorm, it is required not only to turn off the PC, but also ALWAYS disconnect the modem from the telephone line.

When starting to repair a modem, first of all, you need to visually inspect it. Malfunctions after a thunderstorm are often immediately visible. Look at the pull-up resistor and ICs. Cracks and chips may be visible on them.

After visual inspection, turn on the power. Check if the LEDs are on. Connect the modem to the telephone line.

Immediately after connecting, the modem should not "occupy" the line.Call your landline phone number, for example, from a mobile phone.

If the line is busy, it means that the modem is "busy" the line. If there is no “busy” signal, the loop is not closed and is in its original - good condition. If the modem occupies the line, then you should check the key or relay, or protective elements, diode bridge.

Then check if the modem picks up the phone after the command. Try using the Hyper Terminal program (available in Windows) and issue the ATH1 command to pick up the handset. Make sure your modem has completed it.

After the ATH0 command, the modem should hang up. If the modem does not "pick up" the phone, you should check the resistor, relay, diode bridge, protective elements, key transistor, zener diode.

If the AT commands do not work, then the port chip may be replaced.

If the line supports tone dialing, you can issue the ATDTxxxxx command, or ATDPxxxxx for pulse dialing, where xxxxx is the phone number.

If the modem reported - No Dial Tone, check the zener diode, transistors, if everything is checked and correct, then the microcircuit may be out of order.

If the transformer is out of order, the load resistor - low-impedance resistance - 5-20 Ohm could fail along with it. The contacts of the reed relay may also fail, and the optoelectronic relay has an internal field-effect transistor.

In addition, a zener diode may turn out to be faulty, which can be changed to any one with a stabilization voltage of about 9 V.

For dial-up connection, 56 K modems are used - this type of modems works with a telephone exchange in the same way as a regular telephone.

Distributed products of modem manufacturers ZyXEL, D-Link, ACORP, U.S. Robotics. Modems are available in two versions - internal and external. The internal ones are built into the computer in the same way as the sound and video cards. The modem card is installed in the PCI slot of the MP. An internal modem is also called a win modem or keypad modem.

An external modem is designed as a separate "box" and is connected to a PC using a COM or USB connector. When buying a modem, if it provides only a connection via a COM port, you need to check for the presence of a COM port in the motherboard. Many modern motherboards are no longer equipped with the outdated COM port. If you purchased a modem designed to connect to a COM port, or you still have an old modem for a COM port, and you replaced the motherboard, then purchase a special adapter for connection to connect. Typically, all dial-up modems have a built-in fax function.

One of the best, reliable and convenient programs for working with fax modem -. It only works with a dial-up connection. It does not work via ADSL modem. VentaFax is a very reliable and multifunctional program, intuitive, it has a wide range of office automation tasks.

To transfer a document, it must be converted into a graphic file using a scanner. After receiving a fax, the received file can be easily printed on the printer. A voice fax modem is used as an answering machine, telephone recording device and caller ID.

For signal transmission over long distances and better noise immunity, levels of +12 V for unity and -12 V for zero are used. Signals with such voltages are used to control external modems. In the modem, to power the microcircuits, as a rule, a voltage of 5 V is supplied, for the port to work, a level converter is turned on - special microcircuits.

An external COM modem is powered by its own power supply. The USB modem is powered via USB from a computer. External modems use LEDs (up to 8 indicators) on the front panel to indicate the current state. The decoding of the indicator messages is given in table. 14.1.

Some external modems are equipped with displays, answering machine functions and can work even when the PC is turned off, for example, at night.

Modem LED Messages

Rice. 14.1. Adapter for connecting devices with a COM connector to a USB port of a computer

There is a microcircuit inside the modem that performs two functions. This is a DAC and ADC - converting a binary code into an analog signal and vice versa. This operation is implemented by DSP (Digital Signal Processor) - a digital signal processor. The second task that the large integrated circuit of the modem performs is interaction with the PC and self-monitoring. In older modems, these two functions were split between separate microcircuits.

For galvanic isolation between the modem and the analog telephone line, transformers are installed on it - a matching unit. It is usually designed for all kinds of communication standards when using a modem in different countries.

The modems are equipped with memory chips. This is a non-volatile memory that stores the modem control firmware (firmware), which includes sets of commands and data for controlling the modem, all supported protocols and an interface with a computer. Modem firmware update is available in most modern models.

In order to provide the possibility of flashing, flash memory - ROM is used for storing firmware. It allows you to update the firmware of the modem, fixing errors of developers and expanding the capabilities of the device. Some external modem models also use it to record incoming voice and fax messages when the computer is turned off.

NVRAM is a non-volatile, electrically programmable memory that stores modem settings. The user can modify them with the AT command set.

RAM is the modem's random access memory; it is used for buffering the received and transmitted data, the operation of compression algorithms, etc.

Win-modems are deprived of ROM with firmware, in this case it is stored in the memory of the computer to which the modem is connected. It works only if the drivers are installed.

The modem dials the number using either pulse or tone dialing.

Pulse dialing is a method of dialing a telephone number, in which the digits of the dialed number are transmitted to the PBX by sequentially closing and opening the telephone line, the number of pulses corresponds to the transmitted number ("0" is transmitted in ten pulses). Pauses between numbers are encoded with a longer pause.

The signal is generated by closing the relay. It can be: electromechanical, reed switch or optoelectronic. In this case, the relay contacts can be closed to the load resistor or switched.

Tone Dialing - Dual-Tone Multi-Frequency (DTMF) is a 2-tone analog multi-frequency signal that is used to dial a telephone number.

ADSL - modem. This is a modern modem that uses a telephone line. At the same time, you can connect a regular modem (dial-up) to the same line in parallel, or make a connection, receive a fax, etc., while the ADSL modem is operating.

Such a modem usually connects to a PC via a USB port. More functional modems have and / or are connected to the connector of a PC network card, and act as a network hub. ADSL modem works on the principle of frequency division of channels. Data transmission is carried out at high frequencies, the person does not hear them.

Typically, an ADSL modem is connected to the line through a special splitter that separates the input signal into a signal from the PBX and a digital ADSL signal. In the opposite direction, the splitter adds both signals and sends them to the PBX via the telephone line. Additional telephones that are connected to the line before the splitter must be connected through a microfilter to eliminate interference from them.

Modulation Protocol - A modem communication protocol allows modems to exchange data with each other. The protocols define the order of communication establishment, modulation method, data transfer rate, interleaving of data and signaling, and also the end of a communication session.

A modern modem can work with one of the following protocols: V.92, V90, V.34, V.32bis, V.32, V.22.bis, V22, V.23, V.21, Bell 212A, Bell 103.

The MNP (Microcom Network Protocol) protocol allows for error control and other service functions supported by the modem at the hardware level, which ensures high-quality communication on noisy telephone lines.

V.90. The data transfer rate from the provider to the modem is up to 56 Kbps. This data transfer rate is available when using a digital PBX. Data transfer rate from user to provider up to 33,600 bps. In V.90 modems. V.42bis protocol (advanced MNP) is used for error correction, data compression.

V.92. The data transfer rate from the user's modem to the provider is up to 48 Kbps using the V.44 protocol for error correction and information compression. The V.44 protocol compresses data more efficiently than V.42bis. When using it, the download speed of HTML pages can reach 300 Kbps. Thanks to the V.92 protocol, the modem remembers the parameters of the line, which makes it possible to halve the connection time when redialing.

All modems provide support for older protocols. When, when trying to establish a connection, the modem cannot connect, it selects the previous protocol, respectively, the slower one.

All mobile operators that offer Internet access via the 3G network (MTS, Megafon, Beeline, etc.) have a certain coverage area. If you are behind it, your internet connection will be very weak, your connection will be unstable, and your speed will be slow. In such cases, you can use options that will enhance the signal of the 3g modem.

The first option, how to amplify the signal of a 3g modem with your own hands, which you can try at home without unnecessary waste and effort, is to use ordinary sound speakers. Mobile Internet users noted that if you move them closer to the modem, the signal level increases by 10-20%. This is not very much, but if the connection quality is poor, it gives a tangible increase. To get rid of annoying clicks from the speakers, the sound should be set to a minimum.

Another way, how to easily amplify the signal of a 3g modem with your own hands, will require you a little more action than the option with speakers. You need to make a structure of wire and a tin can, which would act as an antenna. The algorithm of actions is as follows:

1. Take copper wire (preferably a long piece).
2. Open the gadget and make 5-6 turns around the SIM card.
3. Pull the other end to the window.
4. Take a tin can or cut off the neck to create a "glass". He will act as a reflector that enhances communication.
5. Tie the free end of the wire to the bottom of the can.
6. Rotate the neck towards the direction of the nearest operator's tower. The increase in the quality of the Internet will be up to 90-95%.

Before tinkering with antennas with your own hands, you should try another method, how to enhance the signal reception of a 3g modem. Some mobile Internet users do not know that by default, when the connection quality is low, the device automatically switches to 2g communication mode, with which it is impossible to work normally. In this case, the transition occurs even in the presence of 2-3 "sticks". To avoid such situations, it should be clearly indicated through the device settings that only a 3g connection should be used. To change an option:

1. run the network setup program;
2. select the "Connection" tab (or with a similar name);
3. then the network search mode must be changed from automatic to 3g.

This will force the device to only operate on those frequencies, without dropping the connection to a slower speed. Some modems do not have such an item in the application interface for the device. In this case, you should look for a combination to activate the built-in command in the instructions for the device or in specialized forums. Each modem model has its own order of enabling the option.

This is not the best, but a working way to easily amplify the signal of a 3g modem with your own hands.Suitable for people who do not want to disassemble, re-solder their device. The design works on the principle of a satellite dish. To make it you need to buy a "reflector" (jar, bowl, CD), USB cable "mom-dad" 3 meters. The creation process is as follows:

1. In the middle of the disc, make a mount for a USB flash drive, or tape it with tape.
2. Connect one end of the cable to the computer and the other to the modem.
3. You can use a stick instead of the holder, or simply attach the disc from the street side to the front of the house.
4. Point the flash drive in the direction where the signal is strongest.

The increase in connection quality is not very large, because the USB cable loses some of it due to the length, but it still improves the connection. The mirror surface of the CD acts as an amplifier. It is recommended to use a bowl instead of a disc because its reflective surface is larger and the reception will be even better. Enamelled options are not suitable, use stainless steel products.

Operators are aware of communication problems, so they are constantly trying to expand the coverage area. As an intermediate solution, for example, a 3g signal amplifier was created for the Megafon modem and other companies. This is an antenna that operates at the required frequencies, and you need to connect it directly to the device. When choosing a model, you should rely on the characteristics of the radiation pattern and gain.

For effective operation of the antenna, it must be directed towards the tower of the mobile operator, which is closest to your home. Attach the stand so that the pins are perpendicular to the ground. Note that the longer the cable length, the greater the signal loss along its length. A short cord will provide sufficient connection gain, provided it is of good quality. If you bought an amplifier, then you should not save on the cable.

The most effective is amplification using a special device - a 3G repeater. Amplification is possible only if the phone picks up at least a minimal 3G signal. This approach can be called fully professional, since after installing the repeater you will receive:

• maximum possible amplification of the 3G signal;
• the maximum speed of the mobile Internet that a mobile operator is capable of providing;
• stable reception area within the coverage radius of the internal antenna;
• getting rid of problems that arise with a weak signal: disconnections, subscriber inaccessibility, interruptions during a call and others.

A repeater is an amplifier of a cellular communication and Internet signal for a summer residence, house or apartment, which in itself is only a part of the 3G signal amplification scheme. To create a full-fledged system, you will need an external antenna that picks up the cellular operator's signal from the base station and an indoor antenna that “distributes” the cellular signal to subscribers indoors. All this is commutated with a coaxial cable. In difficult cases, boosters, attenuators, splitters and other equipment may be needed. In usual cases, for example, to amplify a 3G signal in a country house or in a cottage, it is enough to buy a ready-made kit, for example, VEGATEL VT-3G-kit. This kit is optimal in terms of price / quality criterion, it works reliably and you can easily install it yourself. VEGATEL equipment is manufactured in Russia and has all the necessary certificates.

Another option, how to amplify the 3g modem signal with your own hands, is to use additional devices to connect to the internal antenna. Every such device has it, but some have an open connector, you can easily connect to it, while in others it is hidden in the case, and you will have to re-solder part of the device to use it. In the first case, you just need to buy an amplifier or use a TV antenna as a receiver.

If the connector does not exist, then you can take the device to a service center, where, for an acceptable fee, the wizard will make it possible for you to connect a repeater, which will improve communication with the nearest operator's tower.The main disadvantage of the method is that it will no longer be possible to use the modem only with an internal antenna, so you only need to decide on such a step if you know for sure that you will no longer need it.

Every summer I leave for the village with my children, but I have to go online every day. The operator's tower is far from us, so the connection speed is terrible. I made myself an additional antenna from a yusb cable, a mast and a huge bowl. The connection quality has increased by 30-40%, it could have been better if the USB cable had been a little shorter.

I am often on the road, so I use mobile internet. I noticed that sometimes the speed dropped a lot, it turned out that my modem was automatically switching to a 2g connection. After setting to use only 3g frequencies in the settings, the situation has changed for the better, although in "blind" places the connection still drops to zero.

I live in a hostel, everyone uses the Internet, so a good connection is impossible without additional devices. I used a simple copper wire, which I wrapped around the SIM card in the device, and a large shiny dish (it got from my mother). I just brought this "miracle" through the window and directed it towards the tower, the signal immediately became stronger.