How to add a second monitor or phone on Tegui 2-wire BUS

Cómo añadir un segundo monitor o teléfono en BUS 2 hilos Tegui

One of the most valued advantages of the Tegui/BTicino 2-wire BUS system is its expandability: you can add a second monitor — or up to eight — in the same home or office without needing to run new wiring. The same pair of wires you already have installed supports all the indoor terminals.

But adding a monitor is not just plugging it in. There are three critical aspects you must correctly resolve: the physical connection, the address configuration, and the power supply capacity. This guide explains how to approach each one depending on the type of installation.

Homes: the most common case

The most common scenario is a home with a monitor in the living room that wants to expand with a second terminal in the master bedroom or kitchen. In the 2-wire BUS system, this is perfectly possible and relatively simple.

How to connect the second monitor

The second monitor is connected in parallel on the same BUS: the two terminals of the new monitor go to the same two wires as the existing monitor. There is no strict polarity on the BUS, but it is recommended to keep the same color convention throughout the installation to facilitate future maintenance.

If the distance between the connection point and the new monitor is significant (more than 10-15 meters), use shielded 2-wire cable with a minimum cross-section of 0.5 mm². For short distances within the same home, standard installation cable is sufficient.

Address configuration (subaddress)

This is the step most often forgotten and the one that causes the most problems. In the 2-wire BUS system, each monitor within the same home must have a different subaddress. The main monitor usually has subaddress 0 (or the one assigned in the original installation). The second monitor must be set to subaddress 1, the third to 2, and so on.

The configuration is done using the configurators on the monitor itself or, in models with a menu, from the installer options. The Tegui Coding Kit Green Configurators 2-Wire (BTicino 306065) (€13.04) includes the jumpers needed to set the subaddress on monitors that use physical configurators.

Power supply verification

Each monitor consumes between 2 and 4 W in operation. Before adding a second monitor, check the capacity of the installed power supply. If it is at the limit or is an old model, consider replacing it with a BTicino 346030 Compact 2H 2 DIN Power Supply (€98.44) or a BTicino 346050 2-Wire Power Supply with Video Adapter (€155.10) if the installation includes Classe 100 monitors with video.

Monitor options for home

For the second monitor in a home, the most common options are:

Offices: access control in multiple offices

In an office, the usual need is for several people to be able to answer the door from their workstations without relying on a single reception. The 2-wire BUS system solves this elegantly: all monitors receive the call simultaneously and anyone can open the door.

Specific considerations for offices

  • Privacy between offices: in the 2-wire BUS system, when one monitor picks up (answers the call), the others stop receiving the image and audio. There is no eavesdropping between terminals.
  • Additional monitors vs. audio phones: if some stations do not require video, you can combine video monitors at reception with audio-only terminals in the offices. This reduces cost and the load on the power supply.
  • Long distances: in offices with a large floor area, the distances between the BUS connection point and the terminals can be significant. Respect the minimum cable gauge and, if you exceed 100 meters of total BUS, check if you need an additional power supply.
  • Advanced programming: for installations with more than 4-5 terminals or with specific configuration requirements, the BTicino 3501K Configuration Kit (€78.10) makes programming and verification of the entire installation easier.

Recommended layout for a small office (up to 4 terminals)

  1. Outdoor panel at the entrance + BUS power supply in the electrical panel
  2. Video monitor at reception (subaddress 0)
  3. Monitor or audio terminal in office 1 (subaddress 1)
  4. Monitor or audio terminal in office 2 (subaddress 2)
  5. All connected in parallel on the same 2-wire BUS

Industrial buildings: long distances and demanding environments

Industrial buildings present specific challenges not found in residential or office installations: long distances, electromagnetic interference, and the need for the system to operate under more demanding temperature and humidity conditions.

Distances and voltage drop on the BUS

The Tegui/BTicino 2-wire BUS system has a total distance limit depending on the cable gauge and the number of connected devices. As a general reference:

  • With 0.5 mm² cable: up to 100 meters total BUS length
  • With 1 mm² cable: up to 200 meters total BUS length
  • With 1.5 mm² cable: up to 400 meters total BUS length

If the building has several separate areas (office, warehouse, loading zone), consider installing a BTicino 346841 Floor Splitter (€40.57) to branch the BUS and reach each area without exceeding distance limits.

Electromagnetic interference

In buildings with industrial machinery, high-power motors, or frequency converters, electromagnetic interference can affect the BUS. Preventive measures:

  • Use shielded cable with the braid grounded at a single point
  • Keep BUS wiring away from power cables (minimum 30 cm separation, or use shielded metal conduit)
  • Avoid running the BUS near frequency converters or soft starters

Power supply in large installations

In buildings with several terminals distributed in distant areas, a single central power supply may not be enough. The BTicino 346040 2-Wire Audio Power Supply (€81.32) can be installed as a secondary power supply in a remote area to boost the BUS voltage without needing to run a new power cable from the main panel.

Workshops: robustness and ease of use

In mechanical, carpentry, or similar workshops, the priorities are different from those of an office: the system must be robust, easy to use with busy or dirty hands, and resistant to dust and vibration.

Recommendations for workshop installations

  • Monitor location: install the second monitor at a mandatory passage point (workshop entrance, material reception area) where it is easy to see and attend without moving around.
  • Cable protection: in environments with mechanical risk, protect the BUS wiring with rigid conduit or duct. Exposed cable in a workshop has a very short lifespan.
  • Desktop vs. flush-mounted monitors: in workshops where flush mounting is not possible, the BTicino Classe 100 Desktop Stand (Ref. 344692) (€50.76) allows installing the monitor on a shelf or rack without construction work.
  • Ease of operation: in workshop environments, touch screen monitors may be less suitable than models with physical buttons, which are easier to use with gloves or dirty hands.

Installations with extended access control

If the workshop has several access points (staff entrance, vehicle entrance, loading area) and you need to manage them all from a central point, the 2-Wire Audio/Video LCD 7" Concierge Central BTicino Tegui 346310 (€914.44) allows managing multiple panels and monitors from a single 7-inch screen, ideal for installations with reception or permanent surveillance.

Summary: what you need to add a second monitor

Element Home Office Warehouse / Workshop
New monitor or terminal ✅ Always ✅ Always ✅ Always
Configure sub-address ✅ Always ✅ Always ✅ Always
Check power supply ⚠️ Recommended ✅ Necessary ✅ Necessary
Shielded cable ❌ Not necessary ⚠️ Long distances ✅ Recommended
Floor splitter ❌ Not necessary ⚠️ Multiple floors ⚠️ Separate zones
Advanced configuration kit ❌ Not necessary ⚠️ +4 terminals ⚠️ Complex installation

Need help planning your expansion?

If you are not sure which materials you need for your specific case, contact us with the model of your outdoor panel, your current monitor model, and the number of terminals you want to install. We will prepare a list of materials with no obligation.

Most common materials for 2-wire BUS expansions: