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Connect the data link (RJ12)
The CampMatic box connects to the Truma LinBUS with an RJ12 cable. There are three ways to do this — pick the one that fits your vehicle.
Route 1 — Tap it at the CP Plus (recommended):
The easiest route: you never have to get to the Truma heater itself — the entire connection there is dropped, opening the cover included. On the back of the Truma CP Plus panel, unplug the RJ12 cable sitting there and plug it into the input of the RJ12 splitter. One splitter output goes back into the CP Plus using that same cable, the second output runs to the CampMatic box via the additional RJ12 cable. CP Plus and CampMatic then sit in parallel on the same LinBUS without interfering with each other. The splitter and the extra cable are available with your order as the RJ12 splitter set.
Route 2 — Directly at the Truma heater:
If you cannot reach the back of the CP Plus, or there is not enough room behind it for the splitter and plugs: remove the cover above the Truma heater (marked with an arrow and the word "open") and insert the CampMatic RJ12 plug into the right-hand free socket of the Truma heater. No splitter needed for this route.
Route 3 — Replacing an existing Truma iNet Box:
If your vehicle already has a Truma iNet Box and the CampMatic is to take its place, a look at the connection side of the iNet Box tells you which accessory you need. It carries the LinBUS sockets TIN 1 (two sockets side by side) and TIN 2 plus the DC input for the power supply. What matters is how many LinBUS cables are plugged in.
Case A — a single cable plugged in (iNet Box at the end of the bus):
Unplug the RJ12 cable from the iNet Box and remove the box. You are then left with two cable ends, each carrying a male RJ12 plug — your existing cable and the cable of the CampMatic box. The two cannot be plugged into each other directly; an RJ12 coupler (socket to socket) goes in between and the link is done.
Case B — two cables plugged into TIN 1 (iNet Box looped into the bus):
If TIN 1 holds two cables, the iNet Box does not sit at the end of the bus but in the middle of it: one cable comes from the Truma heater, the other carries on to the CP Plus control panel. A coupler will not help here — you need the RJ12 Y-adapter, the part with three sockets. The swap is then particularly convenient: pull both plugs out of TIN 1 on the iNet Box, remove the iNet Box, put those two plugs into two sockets of the Y-adapter and the CampMatic box with its RJ12 cable into the third. Heater, CP Plus and CampMatic then all sit on the same LinBUS. It does not matter which plug goes into which of the three sockets — the Y-adapter wires all three in parallel. You do not need an extra cable: your two existing cables stay plugged in. That is why the Y-adapter is available on its own — the larger splitter set would be more than you need here.
The coupler (case A) and the Y-adapter (case B) are available as accessories with your order. So before ordering, check how many cables are plugged into your iNet Box — that tells you which of the two you need.
Route 1 is shown step by step in the video — plug in the splitter, cable back into the CP Plus, second output to the box. -
Connect 12V power supply
The CampMatic box only needs 12V — but where that power comes from decides whether it runs reliably. A brief voltage dip is enough to make the box restart. A data link to the CP Plus is not required for this.
Recommended — JST-PH plug at the CP Plus:
This puts the box on exactly the supply the Truma itself uses — the most stable source in the vehicle. On the back of the Truma CP Plus control panel, disconnect the red 12V power plug, insert it into the female JST-PH connector of the CampMatic box, then plug the male JST-PH connector of the box into the control panel. Only the supply voltage is used, no data. You choose this connection variant when ordering.
Alternative — 12V cable (red/black):
If you use the cable, connect it to the same 12V supply the Truma is on wherever possible. Otherwise run it directly and fused to the leisure battery.
Please avoid: connecting downstream of a solar charge controller (its load output), and sharing a tap with heavy consumers such as the water pump, compressor fridge or inverter. These are by far the most common cause of sporadic restarts. -
Perform reset
Wait 3 minutes for the CampMatic box to start up. Then in the Truma control panel menu, navigate to Reset → PR SET and start the reset.
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Verify CampMatic detection
After the reset, check the Index menu for a new (third) entry. It must show T23.700 — then the CampMatic box is detected and ready. If not, perform the reset again.
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CampMatic Box
This is the CampMatic box — compact, pre-wired and ready to install.
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Locate the bench seat
The bench seat in the VW Grand California, under which the service compartment is located. This is where the CampMatic box will be installed.
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Remove seat cushion
The seat cushion is attached with hook-and-loop tape. Simply lift it off — no tools needed.
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Unscrew wooden panel
After removing the cushion, the screws of the wooden panel become visible. Remove all screws and lift the panel.
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Unscrew control panel (CP Plus)
The Truma CP Plus control panel is secured with 3 screws. Remove all screws and carefully flip the panel.
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Connect the data link (RJ12)
The CampMatic box connects to the Truma LinBUS with an RJ12 cable. There are three ways to do this — pick the one that fits your vehicle.
Route 1 — Tap it at the CP Plus (recommended):
The easiest route: you never have to get to the Truma heater itself — the entire connection there is dropped, opening the cover included. On the back of the Truma CP Plus panel, unplug the RJ12 cable sitting there and plug it into the input of the RJ12 splitter. One splitter output goes back into the CP Plus using that same cable, the second output runs to the CampMatic box via the additional RJ12 cable. CP Plus and CampMatic then sit in parallel on the same LinBUS without interfering with each other. The splitter and the extra cable are available with your order as the RJ12 splitter set.
Route 2 — Directly at the Truma heater:
If you cannot reach the back of the CP Plus, or there is not enough room behind it for the splitter and plugs: remove the cover above the Truma heater (marked with an arrow and the word "open") and insert the CampMatic RJ12 plug into the right-hand free socket of the Truma heater. No splitter needed for this route.
Route 3 — Replacing an existing Truma iNet Box:
If your vehicle already has a Truma iNet Box and the CampMatic is to take its place, a look at the connection side of the iNet Box tells you which accessory you need. It carries the LinBUS sockets TIN 1 (two sockets side by side) and TIN 2 plus the DC input for the power supply. What matters is how many LinBUS cables are plugged in.
Case A — a single cable plugged in (iNet Box at the end of the bus):
Unplug the RJ12 cable from the iNet Box and remove the box. You are then left with two cable ends, each carrying a male RJ12 plug — your existing cable and the cable of the CampMatic box. The two cannot be plugged into each other directly; an RJ12 coupler (socket to socket) goes in between and the link is done.
Case B — two cables plugged into TIN 1 (iNet Box looped into the bus):
If TIN 1 holds two cables, the iNet Box does not sit at the end of the bus but in the middle of it: one cable comes from the Truma heater, the other carries on to the CP Plus control panel. A coupler will not help here — you need the RJ12 Y-adapter, the part with three sockets. The swap is then particularly convenient: pull both plugs out of TIN 1 on the iNet Box, remove the iNet Box, put those two plugs into two sockets of the Y-adapter and the CampMatic box with its RJ12 cable into the third. Heater, CP Plus and CampMatic then all sit on the same LinBUS. It does not matter which plug goes into which of the three sockets — the Y-adapter wires all three in parallel. You do not need an extra cable: your two existing cables stay plugged in. That is why the Y-adapter is available on its own — the larger splitter set would be more than you need here.
The coupler (case A) and the Y-adapter (case B) are available as accessories with your order. So before ordering, check how many cables are plugged into your iNet Box — that tells you which of the two you need.
Route 1 is shown step by step in the video — plug in the splitter, cable back into the CP Plus, second output to the box. -
Connect CampMatic box
On the back of the control panel, disconnect the red 12V power plug. Insert it into the female JST-PH connector of the CampMatic box. Then plug the male JST-PH connector of the box into the Truma control panel. The CampMatic box is essentially connected in-line with the existing power supply.
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Reattach control panel
Reattach the control panel with the 3 screws. Then wait 3 minutes for the CampMatic box to start up.
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Perform reset
In the Truma control panel menu, navigate to Reset → PR SET and start the reset.
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Verify CampMatic detection
After the reset, check the Index menu for a new (third) entry. It must show T23.700 — then the CampMatic box is detected and ready. If not, perform the reset again.
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Power on CampMatic Box & wait
Connect the CampMatic box to power and wait approx. 3 minutes until the device has fully booted and the access point is ready.
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Connect to CampMatic Access Point
Connect your smartphone or laptop to the CampMatic WiFi network. The password is on the sticker on the CampMatic box or in the CampMatic app on the status page.
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Open configuration page
Once your device is connected to the CampMatic network, open http://192.168.4.1/ in your browser. You will be asked to log in — username: admin, password: found on the sticker on the box or in the CampMatic app on the status page.
Important: If after login you see the normal control panel instead of the WiFi selection, open http://192.168.4.1/captiveportal directly — this will show the WiFi selection. -
Connect to WiFi network
Select your WiFi network and enter the password. The CampMatic box will connect and display the local Truma control panel once connected successfully.
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Change WiFi later
If you want to change the WiFi network later: The CampMatic box automatically opens its own access point when the configured network is unavailable. Reconnect to the CampMatic network and open http://192.168.4.1/captiveportal to configure a new WiFi network.
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Prepare SIM card
Before the 4G CampMatic box can be used, a SIM card must be inserted.
Important: The SIM card must not have a PIN lock. Otherwise the box cannot register on the mobile network. How do I disable the PIN lock? -
Open the box while powered off
Disconnect the CampMatic box from power before opening. Undo the two Phillips screws in the lid (they sit diagonally opposite, see image) and take the lid off. Lift the lid slowly: the GSM antenna is mounted on the lid and connected to the board by a cable — do not pull on that cable.
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Open the SIM slot
The board is now exposed. The SIM card holder with its metal cover sits in the middle right. Using your finger, carefully slide that cover in the direction of the arrow (see image) — the holder can then be flipped up.
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Insert SIM & close the box
Insert the SIM card with the contacts facing down (watch the beveled corner). Close the holder and slide the cover back against the arrow direction until it clicks. Carefully reattach the lid — do not pinch the antenna cable — and fasten it with the two screws.
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Power on CampMatic Box & wait
Reconnect the box to power and wait approx. 3 minutes until the device has booted up and registered on the mobile network.
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Connect to CampMatic Access Point
On 4G devices the access point is always active — no WiFi configuration is required. Connect your smartphone or laptop to the CampMatic WiFi network. The password is on the sticker on the CampMatic box or in the CampMatic app on the status page.
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Open local control panel
Open http://192.168.4.1/ in your browser. Log in with username admin and the password from the sticker or CampMatic app. The Truma control panel is shown locally — the 4G box talks to the CampMatic cloud directly over cellular, independent of any local WiFi.
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Open registration page
Go to campmatic.de/app/register.php and fill out the registration form. The PIN for registration is on the sticker on your CampMatic box.
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Verify email address
After registration, a confirmation email will be sent to the email address you provided. Click the link in the email to activate your account. Check your spam folder if needed.
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Log in and start heating
After verification, log in at campmatic.de/app and start controlling your heater.
Your CampMatic publishes its readings and controls over MQTT, so Home Assistant can read them and operate the heater as well — the Truma entities even appear on their own once the connection is up.
The detailed guide now lives on a page of its own, where every step was carried out on a freshly installed system and documented with screenshots.
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To the complete guide
We worked through the entire setup on a freshly installed Home Assistant and turned it into a guide of its own — twelve chapters from the first connection to the finished dashboard.
It covers: setting up Mosquitto, connecting to the CampMatic broker, fixing the Truma cards, adding gas bottle, indoor climate, house battery and Truma LevelControl, building the dashboard, troubleshooting. Plus every file for download and screenshots from a real installation.
To the Home Assistant guide ›
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Set up the sensor with its manufacturer app
CampMatic supports additional Bluetooth sensors: Truma Level Control and Mopeka gas level sensors (e.g. Mopeka Pro Check), BM2 battery monitors for the onboard/leisure battery and Ruuvi environment sensors (temperature, humidity, air pressure).
After purchase, first set up the device with the manufacturer's app on your smartphone (e.g. the Truma, Mopeka, BM2 or Ruuvi app). This activates and calibrates the sensor over Bluetooth. You only need to do this once — afterwards the device is detected by CampMatic permanently.
For the Truma Level Control this step is mandatory, not optional: the bottle type is selected in the Truma app, and only from it does the sensor compute percent and kilograms. CampMatic only reads that value and cannot override it — as long as no bottle type is set there, the reading stays empty. -
Add the device in CampMatic
In CampMatic open Settings → Devices and choose Add device. Select the matching device type (Truma Level Control, Mopeka gas sensor, BM2 battery monitor or Ruuvi environment sensor). You can add multiple sensors — e.g. a main and a reserve gas bottle, several batteries, or multiple environment sensors; up to eight per gateway, of which up to four battery monitors. Level Control and Mopeka can be mixed.
The Truma Level Control pairs in two stages: it shows up in the scan on its own. Once it appears in the list, press the button on the sensor once — the credentials are then read out, which takes about a minute. When it says “ready”, tap it and save. It requires firmware 1.22 or newer on the CampMatic box; with older firmware the type is not offered at all. -
Automatic detection & dashboard display
CampMatic then finds the sensor automatically when in range and shows it as its own tile on the dashboard — with live values such as gas level and bottle temperature, battery voltage and state of charge (SoC), or temperature, humidity and air pressure.
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And in Home Assistant?
In the CampMatic app you are done — fill level, state of charge and climate values are computed server-side and show up in the dashboard on their own.
If you want the sensors in Home Assistant as well, some manual work is required: the three BLE integrations publish on dedicated raw topics without auto-discovery. The Home Assistant Integration section has a tab for each — Gas bottle (Mopeka), Battery (BM2) and Climate (Ruuvi) — with complete YAML examples, the conversion formulas, ready-made Lovelace cards and automations.
There is no tab for the Truma Level Control yet. It already does the maths in the sensor and publishes finished values (percent, kilograms, remaining range) on its own MQTT topics — a detailed guide will follow.
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The Truma does not detect the CampMatic box (no T23.700 entry)
After connecting, wait about 3 minutes until the box has fully started. Then run Reset → PR SET in the Truma control panel menu and check the Index menu for a new (third) entry showing T23.700. If it does not appear: check that the RJ12 connection is seated properly and repeat the reset. If you wired it through the splitter at the CP Plus, both splitter outputs must sit tight and the original cable must be back in the CP Plus; if you connected directly at the heater, the plug belongs in the right-hand free socket (see Installation).
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No WiFi selection appears after logging in
If the normal control interface appears after logging in to the configuration page instead of the WiFi selection, open http://192.168.4.1/captiveportal directly — the WiFi selection is there.
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Box is offline / WiFi network has changed
As soon as the configured WiFi is unreachable, the box automatically opens its own access point (SSID and password are on the box sticker and on the app status page under "Fallback WiFi"). Connect your phone to it and open http://192.168.4.1 — you can control the heater locally without internet there and store a new WiFi via /captiveportal. An offline notification is triggered once the box has not sent data for more than 5 minutes (once per offline phase).
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The box keeps restarting
This is almost always down to the 12V supply, not the box. A brief voltage dip is enough to trigger a restart — and it often goes unnoticed in the vehicle.
Typical culprits: the load output of a solar charge controller (it regulates and cuts off entirely on low-voltage protection), a tap shared with heavy consumers such as the water pump, compressor fridge or inverter, plus long thin supply leads and loose crimp connectors.
The fix: put the box on the same 12V supply the Truma uses. The easiest route is the JST-PH plug at the CP Plus — that is the recommended connection variant. If you use the red/black 12V cable, run it directly and fused to the leisure battery, not downstream of the solar controller. Details under Installation. -
The 4G box does not connect to the cellular network
Most common cause: the SIM card still has PIN protection enabled. Disable the SIM PIN in a phone first (iOS and Android instructions in Setup, 4G Box tab). Also check that the SIM is inserted correctly and has credit or an active data plan.
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Registration or password email does not arrive
Check your spam folder first. You can get a new app password via "Forgot your password?" on the login page — the link in the email is valid for 30 minutes. The credentials for the box's local configuration page (user
admin) are on the box sticker and on the app status page. -
Setting up the Telegram bot and its commands
In the app: Settings → Telegram → "Link Telegram", then tap "Open Telegram" and press "Start" in the @camp_matic_bot bot (the link is valid for 10 minutes — the connection is detected automatically). Commands:
/status(temperatures, heating status — including gas bottles, onboard battery and climate sensors if paired),/control(button panel for heating, water, energy mix, fan),/set 22(room temperature 0–30 °C,/set 0= off),/helpand/unlink. Multiple Telegram users per device and multiple devices per chat are supported. -
Configuring notifications
Expand the "Notifications" card on the dashboard. Email and Telegram can be enabled separately for each event: box offline, target temperature reached, heating/hot water switched on or off, room temperature below/above a freely selectable threshold (e.g. frost protection at 5 °C). Paired sensors get their own rows: gas level (Truma Level Control, Mopeka), onboard voltage (BM2) and sensor temperature (Ruuvi). Note: temperature alerts only work while the heater is switched on. Use "Test Email" / "Test Telegram" to verify delivery right away.
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Heating schedules and timers
Open "Scheduler" at the top of the dashboard. You can schedule room heating and hot water (on/off with target temperature), energy mix and fan mode — daily, on specific weekdays or once, to the minute. Schedules run server-side in your time zone (configurable in Settings) — the box itself stores nothing. If the device is offline at the scheduled time, the schedule is skipped and you are notified. One-time schedules delete themselves after execution; the history is on the status page.
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Do I have to get to the Truma heater itself?
In the vast majority of cases, no. With the RJ12 splitter the connection at the heater is dropped entirely — you only ever work at the back of the Truma CP Plus: unplug the existing RJ12 cable, put it into the splitter, run one output back to the CP Plus and the other to the CampMatic box. The cover above the heater stays shut. Only if you cannot reach the back of the CP Plus, or there is not enough room there, do you need the socket on the heater itself (see Installation, route 2).
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Do I need the Truma CP Plus?
No. The CampMatic box only needs a 12V power supply — from any source in your camper. The JST-PH connection at the CP Plus is merely a convenient way to tap power; no data connection to the CP Plus is required.
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Home Assistant bridge does not connect
Search the Mosquitto logs for
bridge,tlsandconnectmessages. Look first for the lineConnecting bridge …in the startup log: if it is missing, the bridge file was never read (with the add-on,customize: active: trueis usually missing, or the file sits in/homeassistant/share/mosquittoinstead of/share/mosquitto). On "Connection refused": re-copy username and password from the status page. On "certificate verify failed": the container's CA store is missing — update the image or mount the host CA store.
Not an error, even though it looks like one:Protocol error from ::1: First packet not CONNECTappears on every start of the Mosquitto add-on and is an internal port check. It is never the cause of a problem.
The full steps are in the Home Assistant Integration card under "Verify the bridge".
Have questions or need help? We're happy to help.