A subscriber tube or an apartment intercom device is a component of the intercom system. It is installed in each apartment of a residential building and allows you to conduct a dialogue with the visitor and control the electronic lock to open the door. It is not at all difficult to connect the intercom handset yourself, if necessary. You just need to know a few simple rules.
Subscriber tube design
The subscriber apartment unit consists of two parts. This is a handset and panel, which is usually mounted on the wall next to the front door. The tube can be installed anywhere, you just need to lay a wire around the apartment. Inside the handset are a microphone, a speaker, and a small board with discrete elements. On the panel there is a pick-up lever, and on the tube itself there is a button to open the door.
The electronic lock button can also be located on the wall panel. In modern models, the lever is replaced by a reed switch, and there is a small magnet on the tube itself. Some models may have a handset on switch. On the back of the panel there are two screws marked “+” and “-”. A two-wire line is connected to them.
Connect the wires to the intercom tube with respect to the polarity, otherwise the system will not work.
All entrance intercoms installed in the entrances of apartment buildings are divided into two groups:
- Coordinate
- Digital
Based on the types of intercoms, apartment pipes also have slight differences. In coordinate intercoms, the switchboard installed in the entrance is responsible for the apartment number, and in digital devices, a special microcircuit that is located on the board inside the handset.
Possible malfunctions of apartment tubes
Intercom device (UKP) is a completely reliable device that can last for many years, but may arise during operation.
The most common defects include the following:
- Mechanical damage to the tube
- When you pick up the handset, the call remains ringing
- Lock control button does not work
- Call is canceled when the lock button is pressed
- Poor audibility
The cost of a handset for an intercom starts from 270-300 rubles, so in case of severe mechanical damage it is easier to purchase a new device than to repair a broken or cracked case. When, when picking up the receiver, the call signal continues to sound, there is no voice communication with the visitor and the electronic lock button does not work, this means that the pickup switch is not working properly.
Many craftsmen repair it on their own, but if there is no appropriate tool and work experience, then it is better to invite a master.
If the electronic lock is triggered only after a few presses, then the microswitch is faulty. The door opening button can be located directly on the tube. In this case, the microswitch is soldered on the printed circuit board. You can replace it yourself. It is necessary to alternately warm up the four contacts with a soldering iron, while squeezing the case with a flat screwdriver. It is quite simple to change the button located on the main panel.
Reason for canceling a call when you press the electronic lock button, there may be a break in the wire coming from the speaker. In the event of any malfunctions, you should first check the reliability of all rations in the tube, and the connection of the line to the lamella on the back of the wall unit. Poor audibility may be due to a defect in the microphone or speaker, as well as contamination of the "Balance" trimmer on the tube board. This potentiometer is not available in all models, but if it is installed, you can, remembering the position of the slider, turn it left and right. In many cases, normal hearing is restored.
Replacing the doorphone tube
When installing an intercom on the entrance door of an apartment building, all work is performed by the masters of the corresponding organization. They also install apartment intercoms.
Therefore, self-replacement of the intercom tube comes down to a few simple steps:
- Purchasing a new tube
- Installing it instead of the old one
- Connecting two wires
Before buying a new handset, you should find out the type of intercom. Models designed for coordinate and digital intercoms have a structural difference. The sales assistant will always tell you which handset is suitable for a specific intercom model.
If you plan to transfer the tube to another place, then the main thing is to observe the polarity when connecting. For any model of the subscriber device, only two wires are suitable, which are fixed with screws on the back of the main panel.
If replacing the tube for a coordinate intercom requires only connecting wires, then installing a tube for a digital intercom includes dialing the apartment number. Open the tube body carefully. There are pins numbered 1-2-4-8 and so on on the board in a row. Using jumpers (jumpers), it is necessary to short-circuit the pairs of pins so that the sum of the dialed digits equals the apartment number. So for apartment No. 7 the first three pairs of pins must be closed.
Conclusion
Self-replacement of the intercom tube is quite possible even for a layman. The main thing is to choose the right model for replacement and not to confuse the polarity of the connection.
Intercom systems are an essential element when creating a security configuration for your home.
The presence of an intercom on the front door will exclude the entry of third parties into the house without the knowledge of the owners.
Such security systems are most popular in apartment buildings, as well as private estates.
One of the key elements of the intercom system is the handset. It can be used to support duplex communication between the owner of the apartment and the guest who came to him, as well as remote control of the electromechanical lock of the front door.
Today there are many different options for the execution of intercom handsets. Consider their features and nuances of choice.
How the intercom handset works
To understand how the intercom handset works, let's consider what types of this device are, and what are the differences between them.
The handset for the intercom is the element through which the communication between the guest and the apartment owner is maintained after the corresponding apartment number has been dialed on the entrance panel of the intercom.
After the conversation, the owner of the apartment can remotely open the front door using the corresponding button on the handset. In addition, the handsets allow you to adjust the volume and melody of the ringing signal, turn off automatically at night.
Types of intercom handsets
Today, intercom systems use two types of handsets - analogue pointing devices and digital.
Analog
To connect these devices, a special crossbar switch is required, the operation of which is similar to an automatic telephone exchange.
The presence of the switch allows you to process the signal from the external intercom unit and redirect it to the intercom handset located in the apartment, the number of which was dialed on the front door dialer.
An analog doorphone tube is more complicated to install, since additional cabling will be required from the switch to each apartment.
With the help of these tubes, you can maintain duplex audio communication, adjust the volume of the conversation and the ringing signal, and remotely control the front door lock.
Digital
The digital intercom handset is designed for use as part of more advanced intercom systems.
They are designed for use in apartment buildings, where there is a need to connect several subscriber handsets to one doorphone input unit without laying a large number of cables.
The main advantage of such handsets is their ease of installation and the ability to quickly connect to the intercom system of a new subscriber point.
Despite the ease of installation of such tubes, it is important to correctly connect all jumpers when installing a new tube or when replacing a broken one. If an error is made during connection, then such a device will not function correctly, and moreover, it will affect the operation of the entire intercom system, which will also work incorrectly.
Like an analog tube, the digital device also allows you to control a remote electromechanical lock, adjust the volume of the input signal, change its melody, increase / decrease the volume of duplex communication.
Intercom tube diagram
The doorphone handset has a simple structure similar to that of a conventional landline telephone handset.
The intercom handset circuit includes a speaker for sound reproduction and a microphone through which voice messages are transmitted. The speaker with the microphone is placed inside the plastic tube housing.
In addition to the sound system, inside the case there is a call and sound volume control, as well as a button for controlling the operation of an electromechanical lock.
The handset itself is installed on a holder that has a handset tongue, as well as a switching board to which the handset's jumpers and the intercom line are connected. When connecting, it is important not to confuse the jumper, as this can lead to incorrect operation of the entire intercom system.
Principle of operation
The audio tube for the intercom works according to the following principle.
When the number of the corresponding apartment is dialed at the front door, the ringing signal is sent to the internal intercom, located in the user's apartment.
If you pick up the handset, you will be able to maintain full duplex communication, talking with the visiting guest, as on a regular phone.
The ringing signal level and the audio transmission volume can be adjusted using the corresponding button.
If a guest needs to open the door, this can be done using the corresponding remote control button for the electromechanical lock.
What to look for when choosing
When buying a handset for an intercom, you need to consider the following factors:
- design features of the tube - they can be wall-mounted stationary or portable wireless;
- tube material - the service life of the device depends on the quality of the material used;
- tube type - it can be digital or analog coordinate;
- build quality is a very important factor that determines how long the tube will last.
Conclusion
The intercom tube device, like its installation, is distinguished by its simplicity. But this business also has its own nuances, which are well known by specialists from companies that are engaged in the installation and maintenance of intercom systems.
Therefore, in order to exclude the incorrect operation of the intercom system when replacing its tube, it is better to immediately contact the specialists. They will help you choose the best tube option for a specific intercom model, as well as professionally install the device and configure it.
Video: Tubes for intercoms. Differences, connection, assortment
Most recently, I already wrote about the completion of the intercom with the MQTT protocol.
In the comments, Vladimir instalator wrote:
The scheme is clearly not thought out. There is no need to interfere with the tube circuit at all, it is enough to connect the device to the line break and emulate the tube by throwing up the required resistances.For some reason, I overlooked the possibility of imitating the intercom tube, because such an approach really does not require interfering with the circuit of the tube itself, it will be possible to intercept control on the way to it. Moreover, this approach, if necessary, allows you to not use the intercom handset at all. We hung up the device and open the door from the phone. If you wish, you can completely develop the idea to battery power.
By the way, in the previous scheme there was an error (I have already corrected the article), which no one paid attention to, and which led to the unstable operation of the intercom. Sometimes he refused to open the door, and I could not understand the reason. I connected an LED between + and - lines, while the native LED was lifted off the ground when the tube was lifted. Thus, in my version, at the moment the door was opened, the resistance in the line was not high enough (at least I think so) due to the presence of the LED and the intercom panel did not understand the opening signal. I realized this only when I started to draw a new circuit with a "throw in the necessary resistances".
The principle of the tube is well known, I described it in the previous article. The only thing that I may have overlooked is that the panel makes a call to one subscriber at one specific time and waits for him to make a decision. Just like that, without the fact of an incoming call, it is useless to take and give a signal to open the entrance door. This is important, but not everyone seems to be aware of it, as there have been several comments on this.
So, let's begin. The access panel distinguishes signals by the level of resistance in the line; to simulate operation, it is only necessary to throw in the required ratings. I tried to draw a diagram on what I already had in my module: two electromechanical relays and two optocouplers, one of which is deployed to receive a signal.
The implementation looks like this:
I apologize for such a simple diagram of the diagram, to make it easier to explain:
- Relay1 it is necessary to intercept control: if we want to interfere with the operation of the intercom, then we switch the relay, otherwise the tube remains connected and works normally (this also applies to the case when there is no power on our device, the relay is closed to the tube).
- Relay2 in the normal state, it provides ground for the LED and holds a 51 Ohm resistance in the line to simulate the resistance of a lying tube (unless of course Relay1 thrown over).
- When a call comes in, to the microcontroller via optocoupler Call a signal is received and a decision is made. In case of opening, we throw Relay1 and Relay2 into opposite states.
- First, the calling panel is waiting for the tube to be picked up from the base: it's up to the transistor and optocoupler Open... By default, the transistor is pulled to power - open, and in the line there is an imitation of an off-hook ~ 400 Ohm... When on optocoupler Open a signal is applied, the transistor is attracted to ground and breaks the circuit, which is equivalent to an open signal.
I hung up the transistor and resistors with hinged mounting:
Again, I did it on the relay module, which I already had after the first version, with a certain set of relays. Surely the circuit can be optimized, for example, on solid-state relays:
Or something like that, depends on your imagination. You just need to carefully select solid-state relays, because they have a non-zero channel resistance and can have a significant impact at a time when there should be 50 ohms in the line. The channel of a solid-state relay usually has a resistance of 5 to 25 ohms, which will significantly affect the background of the required 50 ohms.
The program has undergone very small changes in terms of eliminating shortcomings and adding a mode Open silently... In practice, most often I used the combination Turn off the sound and Open once, decided to combine the two settings into one: the call is intercepted in silent mode, opens the door and switches back to sound mode.
I placed the board all the same inside the intercom tube, soldered to the main board, since now it is only three wires. I made this one to hide the device inside and use the standard line clamps.
But now this is not necessary, you can hang the device in the line break.
Those interested can try (maybe I'll try it myself a little later) to convert the device to battery power. To do this, you will have to slightly change the scheme and logic of work: a call to the intercom will wake up the microcontroller, which, in turn, will connect to wi-fi and check if there are commands for opening it. If not, then set the status of the call and wait for a decision, and then go back to sleep. Energy costs should not be large, the intercom does not ring so often, the main thing is to make the power circuit correctly. In the case of battery power, no galvanic isolation is needed, all the logic can be done using ordinary transistors. The idea seems to me interesting, because not everyone has the opportunity to supply power to the intercom. Anyone willing to help with the case and the mobile application? You can try to cut it into a series.
In general, I am very pleased with the resulting craft, and it is also stitched through the air - it's a pleasure. I invite you to a discussion.
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The purchase and installation of intercoms by specialists with cable laying will be very expensive for the family budget, so to save money, you can try to assemble the intercom yourself using the scheme. The question often arises: how to make an intercom yourself, so that in the future it works properly? The answer is simple: you should carefully follow all the recommendations of the instructions - and the result will be positive.
How to start installing the device?
First of all, you need to find a place where the doorphone will be installed with your own hands, choose the height and determine the distance at which the two connecting devices will be located: the call unit and the subscriber handset. To begin with, with a simple pencil, you should outline the locations of the equipment and the laying of the line. To connect the connecting devices, you need a regular TV cable. An example of connection is the instruction for the factory intercom. Each box with the product contains an approximate version of the connection diagram, which it is advisable to read carefully.
The photo shows an audio intercom
In order to assemble a homemade intercom without assistance, you will need:
- Stationery knife;
- Figured screwdriver;
- Power connector;
- Mating connector and solder circuit;
- Power supply and photo;
- A regular two-core cable (you can use a regular TV cable);
- Soldering iron and wiring diagram;
- Iron box for a homemade intercom.
If the house has been renovated, the main thing is not to spoil the wall covering and compensate for the level of pollution. It is recommended to use a cable duct for laying the cable. All wiring must be started from the box where the power system is located at home. It should be laid along pre-drawn lines. First, the cable channel is fastened at the level to special dowelpairs, if the wall is brick or concrete, then the wires are laid in the gutter. When installing an intercom with your own hands, you can use the usual one - two-core.
You can see how to build an intercom yourself in this video:
How to assemble an intercom handset?
An ordinary telephone receiver is used as a signal receiving tube, from which unnecessary microcircuits are removed and only the speaker and microphone are left. It is necessary to study the instructions: how to make sure that the internal boards in the tube are removed, and leave the dynamic head and microphone from all components. It turned out to be a simple homemade version. In this case, the tube acts as an internal amplifier through which the signal will be transmitted. In order to send or receive a signal, the communication transmission button is used - two-way. When pressed once, information is received from behind the door, when pressed again, the visitor hears the owner of the house.
The contacts are alternately soldered to the button with a soldering iron. A three-core cable with a shield function is used to connect the contacts. You can turn down and add the call volume through a special resistor. With this type of connection, the diagram will help.
You can view the intercom tube diagram in this video:
External amplifier and power supply
The role of the external amplifier will be performed by specially mounted preamplifier boards in an iron box, which are located strictly in a certain order. A preamplifier is installed on the left side of the box, and an amplifier on the right side. The buttons for adding sound and wires go to the outside of the box through specially cut holes. The wires in the box must not touch each other to avoid causing interference. The amplifier is mounted in the simplest homemade intercom.
We close the box with an iron lid, having previously cut a hole for the TDA radiator. The radiator must be insulated, otherwise a short circuit may occur - and no circuit will help.
Do-it-yourself power supply, also in a metal case. The power supply consists of two smoothing capacitors: a low-power transformer and a line filter. Due to the fact that the power supply is in an iron case, the hollow screen does not interfere.
The photo shows a prefabricated intercom - In the lower right corner - receive-transmit button;
- In the upper right corner - outputs of volume 1 (external speaker) and volume 2 (internal speaker);
- In the upper left corner is a resistor.
There is only one resistor in a homemade intercom. To switch it, it is enough to insert a relay with three contacts and simply transfer the resistors to the central core. We make the output and input to the relay in such a way that a simple selective communication is obtained. By reversing the polarity, you can hear both the visitor and the owner of the house alternately. Most often, the intercom is mounted from the side of the entrance near the door on the right side at a level of 120-150 cm or on a fence near a wicket or gate. And how to make the mounts, you decide for yourself.
The electromechanical lock can be installed both at the upper corner of the door and in the middle.
The photo shows an electromechanical lock If funds allow, a factory electric lock can be used to control the entrance to the house, which is powered from a separate power source. Two wires are connected to the lock without polarity difference. The electromechanical lock is mounted on special screws that come with the kit. Two electric wires leave the lock, one of them leads to the power supply unit, the other to a special device-reader, which opens the door with a special key. The second is directly connected to the communication device.
A communication line for a do-it-yourself intercom consists of a conventional television cable with a foil screen winding.
Diagram of a homemade device This scheme will help to assemble amateurs - homemade products of any device.