Replace Tegui 374494 Monitor: Compatible Models and Installer's Guide

When we need to replace a Tegui 374494 monitor, the most important point is not simply to find another video door entry monitor that uses two wires. We must check that the new device belongs to the Tegui/BTicino 2-WIRE BUS system and, above all, correctly preserve the home's configuration.

The Tegui Series 8 ref. 374494 is a video monitor for the 2-WIRE system. A documented compatible upgrade is the Classe 100X16E ref. 344786, an especially interesting option when the customer wants to take advantage of the replacement to add WiFi connectivity and mobile management.

In this guide, we will explain what to check before removing the 374494, how to carry out the replacement, and which errors can result in having video and door release but not receiving the call from the entrance panel.

What type of video door entry system is the Tegui 374494?

The Tegui 374494 belongs to Series 8 and operates on the Tegui/BTicino 2-WIRE BUS video door entry system.

This feature is fundamental when looking for a replacement.

We must not interpret “2-wire” as universal compatibility. The fact that two devices use only two conductors does not mean that they can be interchanged. The new monitor must be compatible with the technology used by the installation.

In the Tegui/BTicino 2-WIRE system, the two BUS conductors carry the communication required for the various video door entry functions.

Therefore, for an installer, the first check should be:

• exact reference of the old monitor;
• installation type;
• existing configuration;
• installed entrance panel;
• and functions currently used by the home.

Which monitor can replace the Tegui 374494?

One of the replacements we have specifically documented for the TG-374494 is the:

BTicino / Tegui Classe 100X16E - reference 344786.

This compatibility is particularly useful because it allows the 2-WIRE BUS installation to be maintained while upgrading the indoor station to a connected monitor.

Important: the fact that other monitors also belong to the 2-WIRE range does not mean that we should automatically advertise them as direct replacements for the 374494. Before recommending another reference, we must check the specific characteristics and configuration of the installation.

We can check the availability of Tegui/BTicino equipment and materials at Tegui-Distel.

Classe 100X16E 344786: upgrading the 374494 with WiFi

The Classe 100X16E ref. 344786 is particularly interesting when the user does not want to simply replace the faulty monitor, but to modernize the installation.

The major difference compared with the old Series 8 is the possibility of having connected functions and managing certain video door entry functions via smartphone.

But there is one fundamental detail:

we must not remove the 374494 and throw away its configurators.

In a real enquiry received by our technical service, a user described exactly this situation: they lived in a multi-unit building and wanted to replace their TG-374494 with a Classe 100X16E 344786.

The technical guidance was that the replacement was compatible, but that the small green numerical configurators had to be removed from the old monitor and placed in the same position on the new monitor so that the call would work correctly.

Before removing the 374494: photograph the configurators

This is probably the most important advice for the entire intervention.

Before removing the old monitor, we must photograph its back.

We recommend taking at least:

1. A general photograph of the back of the monitor.
2. A photograph of the BUS connection.
3. A close-up photograph of the numerical configurators.
4. A photograph where the reference 374494 can be read clearly.
5. A photograph of any connection or additional accessory we find.

These images will allow us to reproduce the original configuration and, if a problem arises, check how the equipment was installed before our intervention.

What are configurators used for?

In Tegui/BTicino BUS installations, configuring the internal unit makes it possible to identify how that device should behave within the system.

One of the essential parameters is identifying the internal unit so that the call made from the entrance panel reaches the corresponding apartment.

That is why we may encounter an apparently strange situation:

• the monitor turns on;
• we have a picture;
• we can perform certain functions;
• the door release works;
• but when we press the home on the entrance panel the monitor does not ring.

Before assuming that the new monitor is faulty, we must check the configuration.

We must not make up the home's address

The fact that we are working, for example, in apartment 3 B does not mean that we can directly determine which configurator corresponds to that home.

The address used within the installation depends on how the system was originally configured.

Therefore, when replacing a monitor that was working correctly, the safest option is to document and reproduce the existing configuration.

How to replace a Tegui 374494 step by step

To reduce errors, we recommend always following the same procedure.

1. Confirm that it really is a 374494

Before purchasing any materials, we must verify the reference on the equipment itself.

We should not identify a monitor solely by its exterior appearance, because there are different generations of Tegui video door entry systems with different technologies.

2. Check that the installation is a 2-WIRE BUS system

The 374494 belongs to the 2-WIRE BUS system.

If the original monitor is still installed and partially working, this identification is straightforward.

If we arrive at a home where the monitor is missing, we must be more cautious and inspect other installation components, such as:

• entrance panel;
• power supply;
• monitors in other homes;
• distributors;
• and references of the installed components.

3. Photograph the old installation

Before touching configurators or conductors, we take photographs.

It is a simple operation that can save us a great deal of time if we later need to determine why a call is not coming through.

4. Disconnect the power supply

Before handling the BUS, we recommend working with the installation disconnected from the power supply, always following the relevant technical instructions and safety measures.

5. Remove the Series 8 monitor

We carefully remove the 374494 and leave the BUS conductors accessible.

If we are going to install a model from another series, we must bear in mind that the bracket and mounting points may be different.

6. Install the new monitor's bracket

We position the new base and check:

• leveling;
• position of the conductors;
• available space;
• and coverage of the marks left by the previous monitor.

7. Connect the BUS

We connect the two wires following the instructions for the new monitor, without unnecessarily modifying the rest of the installation.

8. Reproduce the old monitor's configuration

This step is critical.

In the documented replacement of the 374494 with the Classe 100X16E 344786, the old device's green numerical configurators must be set on the new one, respecting their position.

If we do not do this correctly, we may have problems with the call to the apartment.

9. Power the device and make a real call from the entrance panel

We must not consider the intervention complete simply because the screen turns on.

The test must be carried out from the entrance panel.

We check:

• call reception;
• tone;
• screen power;
• image;
• two-way audio;
• door release;
• automatic switch-on, where applicable;
• auxiliary functions;
• and WiFi/app connectivity if we have installed a connected monitor.

Typical problem: the new monitor has an image but does not receive calls

This symptom deserves a specific section because it can lead us to an incorrect diagnosis.

If, after replacing the 374494, we observe that the monitor is powered and some functions respond, but it does not ring when someone calls from the entrance panel, we must first check the configuration.

We will check:

1. configuration switch positions;
2. so that the values match those of the previous 374494;
3. BUS connection;
4. and call operation from the entrance panel.

The old configuration must be documented before dismantling the equipment precisely so that this check can be carried out.

What if the Tegui 374494 has simply stopped ringing?

Before replacing an entire monitor, we should try to determine where the fault is.

There is a real technical inquiry about a Series 8 TH 374494 that had stopped ringing. The technician who inspected the installation diagnosed a faulty handset.

In that case, it was indicated that the handset for the 374494 was not sold separately, although it was the same one used by the Series 8 telephone, reference 374794.

This type of fault reminds us that we must distinguish between:

• configuration problem;
• BUS problem;
• failure of the monitor itself;
• and failure of a specific component.

Not every call-related problem necessarily requires replacing the entire system.

Can a 374494 be installed in place of an old 5-wire monitor?

Not directly.

This is another real inquiry that is especially useful for installers.

A user asked whether they could install a Tegui 374494 where there had previously been a 374400 with five wires.

The technical response was that the two devices belong to different technologies:

• 374400: old 5-wire system.
• 374494: 2-WIRE BUS digital system.

Therefore, we cannot simply replace one with another by choosing two of the five existing wires.

To convert an old installation to 2-WIRE, we must study the system as a whole, and it may be necessary to replace the entrance panel, power supply, and indoor units, although certain existing wires may be reused if their specifications allow it.

Can we connect an external adapter to control the 374494 from a mobile phone?

We also have a real inquiry about this issue.

A user installed an external adapter on a Tegui Series 8 TG-374494 to answer calls from their mobile phone. After it was connected, the image began to show noise or “static”. When the device was removed, the image worked correctly again.

The reason is that we are working with a 2-wire digital BUS. Introducing devices that are not electrically compatible with this BUS can disrupt communication and cause interference or malfunctions.

If the customer's goal is to have smartphone control, it is preferable to consider a connected monitor compatible with the installation, such as the Classe 100X16E 344786, rather than intervening on the BUS with interfaces not designed for it.

374494 or Classe 100X16E: when is it worth upgrading?

If the old Series 8 has broken down, the intervention can be used to ask the customer what they really need.

The professional rule should always be the same:

First, we identify the installation and then choose the monitor.

We must not do it the other way around.

Checklist for replacing a Tegui 374494

Before ordering the new monitor, we can use this quick checklist:

• ☐ Confirm the reference 374494.
• ☐ Confirm the 2-WIRE BUS system.
• ☐ Photograph the configurators.
• ☐ Photograph the BUS connection.
• ☐ Identify the entrance panel if there are any doubts.
• ☐ Check the auxiliary functions used by the customer.
• ☐ Confirm whether WiFi is needed.
• ☐ Check the space and support for the new monitor.
• ☐ Reproduce the configuration correctly.
• ☐ Make an actual call from the entrance panel after the replacement.

Frequently asked questions about the Tegui 374494

Which monitor is compatible with the Tegui 374494?

A specifically documented replacement is the Classe 100X16E ref. 344786. Both operate within the 2-WIRE system, but we must preserve the configuration of the old monitor correctly.

Can I replace the Tegui 374494 with a WiFi monitor?

Yes. We have documented the replacement of the 374494 with the Classe 100X16E 344786. The installation must be checked and the configurators from the old monitor must be transferred correctly.

Does the wiring need to be changed when replacing a 374494?

In a compatible replacement within the 2-WIRE BUS system, we can use the existing BUS. However, we must check the condition of the installation and not assume that any “two-wire” device is compatible.

Why does the new monitor work but not ring when someone calls?

One of the first checks should be the configuration of the internal unit. In the documented change from 374494 to 344786, it is important to place the configurators from the old monitor in the corresponding position on the new one.

Is the Tegui 374494 compatible with a 5-wire installation?

Not directly. The 374494 belongs to the 2-WIRE BUS system. An old 5-wire system uses different technology and may require the replacement of other installation components.

Can I install an adapter to control the 374494 from my mobile phone?

We must not connect external devices to the BUS unless they are compatible with the Tegui/BTicino 2-WIRE system. If we need smartphone functions, it is preferable to use a compatible connected monitor.

Conclusion: what we must remember before replacing the 374494

Replacing a Tegui 374494 monitor can be a relatively straightforward intervention when we know the system, but we must not reduce it to “removing two wires and connecting two wires”.

Reference 374494 belongs to the Tegui/BTicino 2-WIRE BUS and we have documented its compatibility with the Classe 100X16E ref. 344786.

The critical point for the installer is preserving the existing configuration. Before removing the Series 8, we must photograph the configurators and reproduce them correctly on the new monitor.

After the change, the final check must be carried out by making a call from the entrance panel, verifying the call, image, conversation, and door release.

If we need materials to carry out the upgrade, we can check the monitors and components available from Tegui-Distel.