Check the integrity of the twisted pair. Checking utp twisted pair cable using a program, a tester and without devices. The tester is an excellent way to check

Do you know that when installing or repairing a computer network and communications, sometimes you need to check the twisted pair to determine the integrity, the absence of short circuits and the correct crimp? You can check it with special equipment (using lan testers and multimeters). But due to the lack of the necessary device, the cable is checked simple methods at home. In the article we will talk about how to find out the reason for the termination of the cable and how to perform the correct test of the twisted pair different ways.

There is no Internet access: what to do?

What should I do if a window suddenly pops up on the computer monitor, announcing that there is no connection, and the diode on the network board is off? There are a number of options for solving the problem.

First, try plugging in and pulling out the RJ-45 male connector. If there is still no access, then the hope for a bad connection has collapsed, because the reason lies elsewhere. For example, this may be due to a separate network card installed on the PC. Ask why the connection dropped if you didn't? User participation in the shutdown may not be necessary. Instead of you, the following factors will cope with this:

• unstable voltage in your network;
• use of unlicensed programs (their download and launch);
• the presence of viruses on the PC.

How to check it? Eg, Windows users XP can perform the following sequence of actions: Start - Settings - Control Panel - Network connections. During the last step, you can find out if there is a connection to the connection or not. Also, users of this OS can check the correct operation and settings of the network card drivers, because they are variably another cause of connection problems. In this case, the sequence of actions: Start - Settings - Control Panel - System - Hardware - Device Manager - Network cards. Having done last step, make sure there are no warning signs.

The problem with this card can be associated with both lightning and thunderstorms. To do a sanity check, connect it to a working line or install it in a completely different PC. Before that, do not forget about installing drivers for it. Try moving the card to the nearest slot on the board, as this sometimes helps.

If all these methods do not solve the problem, contact your ISP's support team. Perhaps the reason is failures on their lines. But if everything is fine with this, then the problem is in the violations of the twisted-pair cable. Among such faults are:

• one or more wires break completely, which happens very often;
• less often, a short circuit occurs, which can be in one twisted pair between its wires or in the conductors of the pairs themselves, which are closest.

Hence, twisted pair needs renovation. You can do repairs and checks with your own hands without the help of specialists. About how to check twisted pair we will tell further.

Use of verification programs

Often people are looking for some kind of magic tool to help them determine the condition of their twisted pair cable. But few people know that such options are in their computer. This program makes you aware of its existence when you find that there is no connection with the cable. The corresponding inscription is a signal of an open process or a short circuit, which occurs in a twisted pair cable. True, it is impossible to find out exactly where the problem was formed using the program. A malfunction can only be determined independently with the help of special testers, which include MicroScanner Pro, the capabilities of which we will return to later.

If there is unstable connection or very slow, you should monitor the traffic. We recommend using a free innovative program called Network Traffic Monitor. With its help, you can perform the following actions:

• measure data and the speed of their transmission over the network;
• analyze speed changes over a certain period of time;
• save all relevant information on the hard drive;
• the possibility of wide settings;
• maintaining a large number of languages;
• use of various services.

Installing the program will not take much time. All you need is to launch the exe file and click on the button that confirms your actions. After downloading and installation, monitoring will be performed and all the necessary data will be saved. This program is considered the best in the analyzing and diagnosing kind. This is evidenced by reviews from experienced users.

About connecting a PC to an active network using twisted pair

In order to carry out a high-quality, effective test of a twisted pair electrical wire, you need to simply imagine wiring diagram connecting a twisted-pair PC together with another device (hub or additional computer). We suggest that you familiarize yourself with the scheme in detail for a general understanding.

Particularly interesting when checking a twisted pair is the part with the depicted diagram of a card or hub. The RJ-45 connector, which we mentioned earlier, is connected to it. It can be purchased in Russia at the Allotelecom store. Look closely and you will see that the connection of each twisted pair to the transformer itself is carried out in a symmetrical way. This means that there is a middle of the transformer winding, in it there is a tap. It, in turn, is connected to a common conductor using a resistor, as well as a capacitor.

Such a connection guarantees the destruction of interference in the twisted pair, which come in antiphase. Instead, we get a useful signal, the magnitude of which does not change. Another advantage of the transformer schematic diagram is the protection of your equipment from tangling cable wires, short circuits.

On the swing strength and waveform of a twisted pair signal

Many people ask this question, so we will try to give an exhaustive answer. After analyzing the waveform of the information signal, we can draw the following conclusions:

1. The presence of signals of types Rx and Tx with the same shape and a span of two volts.
2. One pair serves as a signal transmission, and the other as a reception, due to the presence of exactly two twisted pairs.
3. If any RJ-45 connector of the cable is pulled out of the device, then the signal stops transmitting automatically.
4. The signal is round.
5. Distance restrictions between different signal points (no more than 100 meters).

From this, the conclusion suggests itself that a signal range of two volts does not pose a danger to a person. In the same way, the closure is safe for the operation of network equipment. And therefore, it is quite possible to check twisted pairs without disconnecting the cable from the network. In this case, you do not need to worry about the loss of equipment performance.

The tester is an excellent way to check

To begin with, take a look at the electrical wire along its entire length, namely, look at how well the crimping is done in the RJ-45 plugs. In the case of poor-quality crimping, contact problems will occur due to wires not fully inserted. Or they can be overlapped in a fixed place between each other, as a result of which the twisted pairs will not close. Couldn't spot the problem at first glance? Then use testers who carry out quality checks.

Today there is an innovative cable tester that has an LCD display. We already mentioned it at the beginning of the article. What is MicroScanner Pro? The tester has many various functions and is intended for testing twisted pairs. Among the standard tests performed are the following:

• determining how correctly the wiring is done;
• determination of the place where the damage is present;
• analysis of the nature of the malfunction (complete breakage of pairs, insufficient length of pairs, mixed up conductors in one and two pairs);
• determination of segment length;
• calculation of 100% of the distance to the place where the fault is present;
• tone generator mode, which traces the electric wire.

Buy this modern appliance Of course, you can, but not always necessary if you have the right tools at hand. This applies to a pointer tester or a digital multimeter. With their help, you will measure the resistance of electrical circuits, voltage, and current (DC and AC). You will be surprised, but checking a twisted pair with a multimeter is the best solution, the success of which is guaranteed.

Multimeter is the best way

First you need to turn on resistance mode. Try to bring the cable ends to a single point. If you succeed, then the check will be carried out in the following order: checking the integrity of all the cores separately; testing each cable according to its color; check for a short circuit following veins. If it is possible to establish a connection between the probes, resistance will be detected.

However, it often happens that it is impossible to bring both ends of a pair into one single point. Then you need to either cut off the connector, or strip the cores at one end, connecting them in pairs to each other. After that, use a multimeter to probe each of the pairs at the other end. If time permits, then take an old computer outlet that has a working connector and short its internal contacts. This avoids cutting connectors and stripping wires.

Checking with a turnout tester

This method is considered the simplest. With its help, dialing is carried out. Both green and orange pairs are affected. Your actions should take place in this order:

1. To begin, remove the RJ-45 connector from the PC network card.
2. Turn on the mode that will determine the resistance.
3. Touch the orange and white-orange wires with the probes of the machine.
4. Wait until the resistance reading reaches 1-2 ohms.
5. Touch the wire green and white-green.
6. Watch for changes in resistance readings.
7. Measure the indicator between the green and orange wires by touching the probes.
8. Expect an indicator from 100 ohms to infinity.

If the measurement was successful and showed results that are completely similar to the example, then the test indicated the working condition of the twisted pairs.

After checking, you need to decide how to proceed. If a pair of green or orange color breaks off, then one pair should be replaced with one that is not used (brown or blue), but only if it is working. To do this, feel free to cut one fork, ring the pairs again, and then cut the second one as well, having carried out a second pair check. This is due to the fact that the short circuit also happens in the plugs, namely in those places where the clamps are made with clamps. Therefore, if after cutting you find a defect, then inspect the entire length of the electrical wire more carefully. Still can't find the damaged area? Then consider replacing the twisted-pair cable with a new electrical wire.

About checking in the absence of a tester

What if the tester or multimeter is only in the store, and cable testing is necessary? We suggest trying a certain technique. To do this, cut off pieces of 10-15 cm in size from each cable end (this includes connectors). Next, release the ends from the sheath by about 5 cm, after which remove the insulation from each conductor for a length of 2 cm.

After preparing the twisted pair cable, take a small container made of glass, plastic or polyethylene and fill it with water. Before this, salt, boiled until completely dissolved in water, should be added to the liquid (there should be a quarter of the volume of salt water). But keep in mind that if the volume of salt is larger, then this is even better, because with its help electrical water resistance is carried out. Next, place the end of the twisted pair wires into the prepared liquid. Please note that the contact of the conductors is excluded, and therefore there must be at least a small distance between them.

As for the ends of the twisted pair, which are on the opposite side, you need to connect in the correct order to any active power source that has a value greater than 3 V. But if there is too much salt in the water, then a value of 1.5 V will suffice. Getting voltage is possible from any sample of a finger-type battery. You can also use a cellular battery (3.7 V). Use the following equipment as a power source:

• resistor having a rating of 50-100 ohms. With it, you will get protection against twisted pair short circuits;
• net telephone communication. It contains the presence direct current and voltage of 40 V, which is safe both for communication lines and for human life. The option is ideal for supplying voltage at the entrance, because there is a telephone box nearby;
• charger for mobile phone;
• computer USB port, having 5 V at the extreme terminals and a load current of 20 A. But note that you can only connect it to a computer with a resistor that limits the current, otherwise the PC will fail.

After the voltage has been applied, you will see what will happen to the other ends of the twisted pair in the water. The conductor connected to the minus should highlight small white hydrogen bubbles on itself. And the conductor that is connected to the plus, highlight the yellow-green bubbles of chlorine. If this happens, then everything is fine with the twisted pair cable and there is no question of a short circuit. If a short circuit is present, then hydrogen or chlorine bubbles will also come from another conductor.

In this way, you will find the twisted pair damage and end the verification process at this point, replacing the damaged pair with a blue or brown sample. Don't know how to do it? If, when checking, you find a break in the orange pair, then connect its place coming from the connectors with a pair of blue cables.

Despite such an elementary method, we still recommend crimping the cable with a new connector instead of splicing. If you do not have it, then you can always buy connectors in Moscow at affordable prices in the Allotelecom online store.

If everything is fine with a pair of green and orange colors and you do not want to crimp, then check the cut pieces of the twisted pair with the connector. To do this, twist together colored conductors that are protected from insulation and separately white wires. After that, stick the connector into the salt solution, completely immersing the contacts in the water. Twist the wires, attach to the battery. Watch for little white bubbles appearing through one on 4 of the 8 contacts. Next, reverse the polarity of the battery connection so that bubbles form where they did not appear before and also through one. If something goes wrong, then this is the first sign of a non-working twisted pair cable. There are no white bubbles on one of the contacts - it means that the wire is broken, and if they are absent at all, then it has happened short circuit.

Potatoes and twisted pairs

First, prepare the twisted pair in the same way as you prepared for the salt solution. Then follow this sequential check:

1. Take half of the raw potatoes, which is needed instead of a container.
2. Push each twisted pair one by one into the potatoes 1-1.5 cm.
3. Keep a minimum distance between wires.
4. Watch what happens around the connected wire: if it turns green near the positive terminal, and whitish foam forms near the negative terminal, then everything is fine with the wires. Well, if there were no changes on the cut, then the twisted pair is broken or shorted.

You can also use half an apple for this experiment. Experience has shown that with its help you can also find out about the health of the twisted pair, although this does not happen as clearly as with potatoes.

Now you know about everyone possible ways twisted pair checks, which are carried out by programs, testers, multimeters and folk methods. In this way, you can check different electrical wires. We hope that this article has become useful for you and now you can easily find out the reason for the breakdown of a twisted pair cable by carefully checking it.

allo-tele.com

Testing a twisted pair cable at home.

During installation and repair computer networks and communications, there is often a need to check the integrity of the twisted pair, the absence of short circuits, the correctness of the crimp, and so on.

Of course, if you have the appropriate equipment (for example, a lan-tester or at least a multimeter), this task comes down to simply connecting the cable to the appropriate device and checking it using standard methods.

But not always the required device is at hand. Sometimes you need to check the twisted pair cable at home, so to speak "on the knee".

Method 1. Checking the twisted pair with a multimeter.

I think that many people at home or in the garage have a multimeter, arrow tester or similar device for measuring resistance, voltage and current in the circuit.

With this device, you can very easily and quickly check the twisted pair cable for breaks, short circuits and overall performance.

The twisted pair is checked by a device operating in the resistance measurement mode.

If it is possible to bring the ends of the cable to one point, then the test will be carried out as follows - first, we will check the integrity of each core separately, for this we will test each cable in turn by color. Then we check for a short circuit with other wires - for this, on one connector we touch one wire, and on the opposite one to each in turn. Resistance should be shown only in those cases when there is contact between the probes (in the first case, it indicates that the core is in order, in the second, that there is a short circuit with the corresponding core).

However, it is not always possible to bring both ends of the cable together at one point, so you can use the following trick: either cut off the connector, strip the wires at one end and connect them in pairs, each pair to each other. After that, probe each pair at the other end with a multimeter. If you have time and desire - you can take the old computer socket with a working connector and close the contacts inside it, this will make it possible not to cut the connector and not strip the wires. Additionally, you can not only short-circuit the contacts inside the socket, but also connect them using resistors with different resistance values ​​- then you can see if there is a short circuit between the pairs. (The resistance on the multimeter will be the value of the resistor + a small increase due to the length of the wire).

Method 2. Checking a twisted pair cable without a multimeter.

If you don’t have a multimeter, but you still need to check the cable, then you can use the “old-fashioned” method: At one end, the wires are stripped to a length of about 5 centimeters and lowered into a glass of warm, highly salted water.

After that, at the other end of the cable, a voltage of more than 3 V is applied to one of the pairs. To do this, you can use a krone battery, a battery from cell phone, a battery from the motherboard. If none of the listed power sources is at hand, then you can use a standard AA 1.5V battery, but then the water must be heavily salted.

The container with water must necessarily be made of a dielectric (plastic, glass).

After power is applied, the following will happen inside the glass: white hydrogen bubbles will be actively released at the cathode (negative pole), while yellow chlorine bubbles will also be actively released at the anode (positive pole). This means that the wires are in good condition, they conduct current and there is no short circuit between them.

Another original way to check is to insert one pair into a potato, to a depth of 1-1.5 cm. And serve food in the same way as described above. After that, white bubbles should appear on the cathode, and the place around the anode connection will turn green.

In fact, there are a huge number of these "folk" ways to check different cables. It would be interesting to know what methods you use, which ones you heard about, etc.

avs-electronics.livejournal.com

How to check for a broken internet cable

If the owner of the PC encountered problems with the Internet and, when trying to connect to the network, sees the error “network cable is not connected”, then most likely there are problems that will be quite difficult to fix on your own. A more reliable sign of cable damage is the absence of an LED signal at the point of entry of the Internet plug. Unfortunately not all motherboards have a light that indicates the connection of a working wire. This is also true for external network cards inserted into the PCE slot that do not have LED indicators.

You can try to solve this problem on your own. To do this, you need to determine what exactly caused the lack of Internet. Here are some of the most common faults that you can fix yourself:

1. Unstable mains voltage. Such a problem leads to many malfunctions in the computer, one of which is problems with the Internet. The solution to the problem is to install uninterruptible source power supply that protects against voltage surges.
2. Use of unlicensed software. One of the most common sources of problems when working with a PC is the use of unverified programs that can lead to errors or contain malware. Therefore, only licensed software should be used on computers used for work and containing important data.
3. Network equipment turned off. Sometimes problems with browsing the Internet can be caused by simple things, such as a disabled network adapter. To check activity this device, you need to go to the "Control Panel" in Windows, find the "Network Connections" item, go into it and select the "Network adapters" tab. On the window that opens, make sure that the adapter is active.
4. There are no drivers for network equipment. This problem especially relevant when reinstalling operating system. To make sure that the drivers corresponding to the network equipment are available, you need to go to the "Control Panel" tab, select "System", open the "Device Manager" menu, find " Network adapter and view its properties. If there are no warning error messages, then the problem is most likely not in the drivers.

All of the above errors can usually be resolved by the efforts of the computer owner.

Help from experts

If the above causes of the malfunction do not fit or you cannot cope with the problem on your own, then you should use the help of professionals. The first thing to do in case of problems with the Internet or the power cord is to call the operator of the provider that provides network access services. Thanks to this, it is possible to as soon as possible find out if the cable is damaged or any other damage.

If, by calling the operator, the owner of the computer found out that there was no problem on the part of the operator, and also checked his PC for serviceability, then it can be argued that the cable is damaged. You can fix the problem using the services of specialists from a company that provides Internet access.

In some cases, wire damage can be repaired on your own. To do this, you need to know the possible types of breakdowns and how to eliminate them. The most common malfunctions that appear when a cable is mechanically damaged are the following:

1. The most common cause is a complete cable break. Usually occurs due to negative mechanical impact, such as squeezing or working at a temperature exceeding the norm for the cable of this type.
2. A short between twisted pair wires. It is also a fairly common cause of problems with the Internet. Also appears due to crushing and blows.

If it was possible to detect a cable break, then you can try to fix the problem yourself. It's also pretty easy to check if it works. network card, which is also often the cause of network problems. To do this, just install it on another computer and connect an Internet cable. But this feature is relevant if you have access to the network through a working wire.

To accurately determine the malfunction of the Internet cable, you must have knowledge of correct connection wires through a switch, hub or other devices, and also have a general knowledge of the principle of transmitting information through a twisted pair cable.

It is also advisable to familiarize yourself with the cable connection diagram. Basically, for wires that transmit any digital data, a transformer connection scheme is used to avoid interference. Thanks to the knowledge of the above causes of cable failure, anyone can fix a malfunction or break in the conductor.

The functional responsibilities of any system administrator usually consist of a whole list of different items, and, depending on the pace of technological progress, some of them go into oblivion, and new ones appear in more complex forms. But one thing has remained unchanged from the origins of computer networks to today is the maintenance, laying, testing and optimization of a structured cable network.

Particularly successful administrators do not have to deal directly with laying: a self-respecting company will always provide this large-scale and responsible work to the integrator firm. But in practice, the situation is rather the opposite - companies are trying to save money wherever possible, and administrators often have to put aside their laptop and console and pick up a puncher and a bundle of cable. Accordingly, putting the laid cable network into operation and testing the connections made also becomes the task of the administrator.

To solve such issues, the administrator must be armed with devices for monitoring network connections and cable parameters, depending again on the generosity of the employer - the simplest, average or professional level.

Unlike the system administrator of a decade ago, who checked the cable cores for breaks with a multimeter, putting a short-circuited connector at one end of the route and looking for this loop in the sockets, a modern administrator has a lot of equipment options available.

Consider the options for cable network testing devices that should be in the arsenal of every network administrator.

For testing telephone cables and twisted pair patch cords.

This device was taken to check exactly the twisted pair patch cords on the connectors RJ-45. It often happens that in the process of work, a wire is bent somewhere, and some core simply breaks off and stops working. Thanks to this tester, you can easily find which jelly is the problem, and if necessary, re-crimp the entire wire, for example, into 4 wires. It is known that patch cords crimped into 4 wires maintain speed 100mb which is fine for the internet. This is very important if the wire is quite long, it is not clear where the break is, and there is simply no way to buy a new one.

Certainly, there are professional testers, which show in which wire and how far the break is, and the length of the wire itself is measured, but this equipment will be relevant for professionals, but such a device is enough for me.

To check, I will use two patch cords, this is a straight line and a cross one. Direct twisted-pair crimp is used to connect a computer to a modem, router, switch, and any other network equipment. This crimp is universal, and supports gigabit speed when using 8 wires, when using 4 wires 100Mb. Crimping it is very simple, the wires match each other, i.e. 1=1, 2=2, etc. The image shows more detail.

For the test, I have a wire with a direct crimp, I will crimp another, the so-called cross crimp. This type of patch cord is used to connect computers to each other without using network switches. The order of crimping the wires can be seen in the image below.

For crimping, we need: crimping tool, two plugs RJ45 and a piece of twisted pair.

We expose the wires according to the picture for cross crimping, cut off uneven edges and insert into the plug.

We put the wire in so that the ends of the wires can be seen from the other end, then, we crimp the wire itself.

Put on and crimped RJ45

In this sequence, we make the second end

Now about the tester itself.

The tester is delivered in a protective case, which is very convenient during operation.

Power is supplied from a 9 volt crown type element. The tester itself consists of two parts, this is the main "setting part" with LEDs and an operating mode switch, and the response, which shows which wire is ringing now. Parts of the tester can be easily separated from each other.

The switch has 3 positions OFF(switched off), ON(work in normal mode), S(slow switching).

Checking the straight cable.

We connect the cable to the connectors, turn on the tester. Lights from 1 to 8 should light up alternately on both parts of the tester. If at some stage a light bulb does not light up, then there is a break in the same jelly.

Checking the crossover cable.

The situation is more complicated with checking the crossover cable. Since the wires there do not consist alternately, as a result, the bulbs will light up in this order:

If we insert the wire in reverse, the sequence will be reversed. In principle, if the light is on, then the contact is already there.

I was very pleased with the possibility of working without using the counterpart. Instead, it can serve as a network card of a computer or other network equipment.

This means that if you connect one end to the network card, the other to the driving part, the lights will turn on one by one, indicating that the patch cord is working, or vice versa, about a break.
By the way, the RJ45 plug also got on aliexpress:

If you need to find a malfunction of equipment or electrical wiring, one of the operations that is performed first is to test the cables and wires with a multimeter (tester) to check the health of the circuit (the absence of breaks in it), the presence of a short circuit and determine its resistance (if necessary ). Thus, it is possible to easily and quickly check the lamp, iron, switch, fuse, transformer for serviceability. How to ring the wires with a multimeter correctly will be discussed in this article.

What you need to know about the device to ring the wires

If you plan to ring the wiring in the apartment, you need to know a few fundamentally important facts about multimeters. First of all, it is worth noting that you can check the wire with the simplest device. An inexpensive Chinese model with minimal features is quite suitable.

But at the same time, it is most convenient to use a device that has the dialing function itself. In order to set the device knob to the appropriate position, it is necessary to turn it in the direction of the diode icon (as an option, an image of a sound wave can be additionally applied). This means that when checking the integrity of the wire, when the contacts are closed, you will hear sound signal.

But the presence of sound accompaniment is completely optional for the continuity of wires with a multimeter. The fact that the circuit is broken will be indicated by a unit on the display, indicating that the resistance level between the probes is higher than the measurement limit. If there is no damage in the area under study, the resistance value will be displayed on the screen, which should ideally tend to zero (provided that it works in household networks of small length).

Call sequence

1. Before ringing the circuit with a multimeter, you need to turn the knob of the device to the desired position.
2. Insert the ends (measuring leads) into the appropriate sockets. The black wire to the jack marked COM (sometimes it can be marked with an "*" or a ground sign), and the red wire to the jack where the Ω sign is indicated (sometimes they put the R sign). It is worth noting that the sign Ω can be applied both separately and in combination with the designations of other units of measurement (V, mA). This is the correct position of the test leads, which will allow you to maintain polarity when making further measurements. Although if only the integrity of the wires is checked, their relative position will not affect the result in any way.
3. Turn on the device. For this, a separate button may be provided or the inclusion may occur automatically when the knob is turned to the desired position when selecting the measurement limits or operating mode.
4. Close the measuring ends together. If a signal sounds, then the device is working and ready for operation.
5. Take the cable or wire to be tested (its ends must first be stripped of insulation, cleaned to a metallic sheen, dirt and oxides removed from the surface). Touch the test leads to the bare areas of the conductor.
6. In case of integrity, a signal will sound, and the readings of the device will either be equal to 0, or indicate the resistance value. If the display shows 1 and there is no audible signal, this means that the tested conductor is broken.

Rules for safe dialing using a multimeter

dialing network cable multimeter

Working with electricity does not allow unprofessionalism, so there is a certain list of rules that allow you to make it as accurate, fast and safe as possible.

1. It is most convenient to use special tips at the ends of the measuring wires, which have received the more common name "crocodiles", when dialing. They will allow you to make contact stable and free your hands when taking measurements.
2. When ringing, the always checked circuit must be de-energized beforehand (it is necessary to remove even weak-current batteries). If there are capacitors in the circuit, they must be discharged by shorting. Otherwise, during the work, the device will simply burn out.
3. Before checking the integrity of a long conductor during measurements, it is important not to touch its bare ends with your hands. This is due to the fact that the resulting readings may be incorrect.

When ringing a multi-core cable, it is necessary to separate and strip all existing cores from both ends. After that, you need to check the circuit for the presence of short circuits in it: for this, a “crocodile” is fixed in turn on each core, all the remaining ones are touched with the other measuring end in all possible combinations.

Check if there is a short circuit between the wires of the cable. If there is no sound signal on the indicator “1”, then everything is in order, otherwise there is a short circuit.

In this case, the sound signal will indicate the presence of a short circuit between the wires being tested. This may not be of practical importance for small cross-section multi-core cables operating in low-current networks, but when working with high voltage it is of fundamental importance.

We call the cable cores. There is a sound signal - everything is fine, otherwise - the core is damaged.

To determine the integrity of the cores, the same operation is performed, only at one end of the cable all the stripped cores are twisted together. When looking for a break, it is important to consider that the absence of a sound signal at any of the ends will indicate a violation of the integrity of the conductor.

We call the wiring in the apartment with a multimeter

Consider, as an example, a modern apartment in which the wiring is made in accordance with applicable requirements and standards. This means that when laying the lines for lighting and powering the sockets, they were separated, and separate wires were laid for them in each of the rooms. Each of these circuits is fed from the apartment panel through a separate circuit breaker.

If the light has disappeared in one of the rooms, first you should check the serviceability of the lamp. Before starting work, it is necessary to de-energize the room / apartment, depending on the power scheme. When using an opaque incandescent lamp in a lamp, it is difficult to visually determine the integrity of the filament, so a multimeter and its continuity function are required. Let's see step by step how to do it right.

First you need to check the shield for the presence of triggered machines. In the first case, they will be in the on position (then the malfunction may be hidden in the room switch, lamp or cartridge). The chance of damage to the wiring in such a situation is low. If the device worked, it will be necessary to check everything except the room switch, including the switchboard itself.

If the machines didn't work

We call the switch. When the switch is on, there should be a sound signal, when it is off - silence and "1" on the indicator.

1. Make sure that there is voltage at the input and output of the machine. If it is, you can proceed to further verification.
2. Prepare the device for operation and check its serviceability by shorting the measuring ends.
3. Unscrew the bulb from the socket.
4. With one of the measuring probes, touch the base (the metal part of the lamp with a thread), and the second - the central contact of the lamp (the insulated center of the end of the base).
5. An audible signal and instrument readings that are other than 0 or 1 mean that the lamp is working. If it is faulty, you need to replace it, which will be the solution to the problem.
6. We check the cartridge for serviceability. To do this, you need to disassemble the lamp, make sure the integrity of the wires and contacts. If everything is in order, then the cause of the breakdown is not in the cartridge. If faults are found, they must be corrected. The lamp cannot be turned on.
7. We check the serviceability of the room switch. To do this, remove the plastic cover, unscrew the screws and take it out of the mounting box. We inspect the equipment for the appearance of soot, check the tightness of the fasteners. If everything is in order, you need to install the measuring ends of the tester on the switch contacts. The appearance of a sound signal when the dialer is on will indicate that the equipment is working properly. The wires may not be disconnected.

During such a check, as a rule, a malfunction is detected, which becomes the cause of all the trouble. Its elimination allows you to quickly solve the problem.

If the machine worked

To ensure electrical safety during work, in this case, the voltage is turned off using a general apartment machine. Next, the serviceability of the cartridge and the wires connected to the lamp is determined according to the algorithm described above. If there are no malfunctions, you need to check the wiring itself using a multimeter and a continuity function. Such malfunctions happen quite rarely, but they still happen, for example, when installing suspended ceilings or decorative interior elements.

The dialing of the wiring in this case is performed as follows.

1. Using a screwdriver, turn off the connected conductor (if installed correctly, it is located below) and take it to the side. The "zero" of this group is, as a rule, on the zero clamp under the machines.
2. We unscrew the incandescent lamp from the cartridge. Using a ready-to-use tester, we check the line by connecting one of the measuring probes to “zero”, and the other to the disconnected conductor. If the device beeps, the wiring is shorted.
3. In this case, in the room under the ceiling above the switch, we find and open the junction box. Disconnect wires.
4. We check all groups of wires for the presence of a short circuit in them.
   To determine the section of the circuit in which there is a short circuit, we again check the circuit on the apartment panel with a multimeter. If the signal sounds, it means that it is the wire laid from the shield to the box in the room that is to be repaired. Otherwise, the search will need to continue until a result is obtained.

Video

From all of the above, we can conclude that the presence of a multimeter with a dialing function in the house is an objective necessity for any home master. With such a device, in most cases it will be possible to quickly eliminate minor malfunctions without seeking help from specialists.

I have been looking closely at such a device for a long time, tk. in the office I work as a system administrator (if anyone is not in the know - system administrator), there is often a problem with a twisted pair cable (they will either press the door, then tear it out of the connector, etc.). This is where troubleshooting comes in.
And this tester in a matter of seconds can determine an open, short, or simply incorrect cable crimping.
So, you can connect cables with connectors to the tester - RJ-45 (twisted pair), RJ-11 (telephone cable), USB and BNC ( coaxial cable).
Equipment:
1 x Tester
1 x Bag
1 x BNC connector
1 x Instruction


The device is powered by a “crown” battery, which is not included in the kit (for $ 16 they could have been included in the kit).
The tester itself looks like this:

There is only one button on it, with the help of which the cable test is carried out, as well as 15 LEDs, which actually serve as indicators.
Tester connectors look like this:


One part separates:


Reverse side:

Battery Placement:


Since I bought the tester mainly for testing twisted pair, therefore I will describe the operation of the device only on twisted pair, which I will spoil a little (which you won’t do for the sake of review), I think when connecting a telephone cable, USB cable and coaxial cable, the principle will be similar.
We connect the cable to the tester only on one side, if the cable does not have a short circuit, the tester will show " no connection" and the orange LED on the side lights up, the upper LEDs do not light up, the green indicator should always be on, showing the battery charge:


If the cable is OK, the blue LED will show " connected":


Making a cable break:


And the blue LED also lights up, but the LEDs on top (orange) will not all light up, signaling " cliff":


Now we make a closure:


The tester noticed this and reported with a red LED, as well as orange LEDs show which wires " close":


Now we will connect the wires, but mix up the colors:


We receive the message " non-parallel", but all orange LEDs are on (it would be better if they made an indication of incorrect connection):

The device also emits beeps:
1 beep - no connection
1 long beep, everything is “ok” (the cable is crimped correctly and there is no short circuit, but a break is not ruled out)
2 beeps - the cable is not crimped correctly
3 beeps - somewhere short circuit
Video:

Now let's analyze the tester:








The soldering is good, but the soldering liquid is not removed.
Subsuming the results:
- I thought it was a bit overpriced.
- It is a pity that it does not display in which place wrong connection
- No battery
+ Instant result display
+ You can connect not only a twisted pair, but a telephone cable, USB cable and coaxial cable
+ Included is a case (under the skin)
+ Can measure a cable up to 100 meters long (more than 100 meters cannot be used at all)
+ Intuitive display of results
+ Sound indication
+ Removable panel (you can test the cable 100 meters from the tester itself).
Conclusion: I liked the tester, now it will be easy to determine a break, poor cable compression, as well as a short circuit. If you are not embarrassed by the high price of this tester, you can safely buy it.

NEVER PRESS