For years the Truma iNet Box was the official way to operate a Truma Combi remotely. If you own one — or are considering a second-hand unit — the first question is usually the same: what can the app actually do?
The answer surprises many people, because the app works quite differently from what you would expect today.
Two modes, one switching point
The iNet Box has exactly two ways of talking to your phone:
- Bluetooth — inside and right next to the vehicle, roughly ten metres
- SMS — anything beyond that, over the mobile network
Truma describes it like this: as soon as you leave Bluetooth range, the app switches to SMS communication. It then phrases the control commands as prepared text messages, and the box replies to them.
Within those ten metres it feels like an ordinary app: tap, change a value, done. The difference starts exactly where you actually need it — when you are not at the vehicle.
What "remote control via SMS" means in practice
Beyond Bluetooth range the app is not a connection to your heater. It is a text template generator: it composes the right message and hands it to your phone's SMS app. The box reads it, carries out the command and sends a message back.
A few consequences are worth knowing in advance:
- The box needs its own SIM card. Mini-SIM, 2G-capable, with its own number — and not included. Your heater effectively gets a second phone number.
- Every action costs two messages. One out, one back. That includes simply checking whether the heating is running.
- There is no live display. What you see is always the state of the last reply, not a continuously updating dashboard.
- No notifications. Unless you ask, you will not hear about anything. The box never contacts you on its own.
- Abroad, roaming applies in both directions, with varying reliability depending on the card and country.
There is no Truma server in between. That is appealing from a privacy point of view — but it also means no push messages, no history and no automation.
What owners struggle with in practice
The same topics have been coming up in motorhome forums for years. If you are considering a used unit, they are worth knowing:
The SIM card. Prepaid cards are effectively the only sensible choice — and that is precisely where owners report rejected SIM PINs. There are multi-page forum threads dedicated solely to which tariff works reliably in an iNet Box.
The box eventually stops answering. A recurring pattern: after days or weeks, replies to status requests simply stop arriving. Some owners later received all the queued answers at once. Often only a hard reset or a full re-setup helps.
App updates. After certain updates, owners reported that the prepared messages arrived empty — the app switched to the SMS app but passed no command. The workaround was copying older control messages by hand.
None of this makes the system bad; it worked for years. But it explains why many owners start looking for an alternative.
Important: Truma has set end dates
The iNet Box has not been produced since 1 January 2023. Truma has announced two further dates for the app and the box:
- 1 January 2027 — no further app updates or maintenance releases
- 1 January 2028 — end of service and support
Truma cites the gradual shutdown of 2G networks across Europe as the reason. That 2G network is exactly what SMS remote control depends on. In Switzerland it was switched off completely back in early 2023 — remote control there no longer works at all today, leaving only Bluetooth on site.
We covered this in more detail: what the 2G shutdown means for the iNet Box.
What an always-connected app looks like
The difference to a current solution is less about features than about the nature of the connection. CampMatic stays online — over WiFi or cellular, depending on the variant. That gives you what you would expect from an app:
- The current state is there when you open it — no request, no waiting
- Temperature, operating mode and hot water can be set directly
- Schedules run without you having to think about them
- Alerts arrive on their own, optionally through a Telegram bot
- If you like, everything goes into Home Assistant over MQTT — voice control is possible there, though it requires a paid cloud subscription or a manually configured setup
- No cost per request — check as often as you like
Your CP Plus panel stays exactly where it is and keeps working. CampMatic plugs into a free port on the heater: no tools, no changes to the vehicle wiring, and the warranty on your Truma Combi remains unaffected.
Supported are all compatible models (gas and diesel alike) with a CP Plus from firmware C4 onwards, in any vehicle — tested among others in the VW Grand California.
Conclusion
The iNet Box app is better than its reputation as long as you know what it is: a convenient Bluetooth remote for close range, and an SMS assistant for everything else. If you only pre-heat occasionally, it does the job.
If you want to see the current state without sending a message first — and would rather not wait and see what happens after 2028 — an always-connected solution is the better fit.
→ CampMatic Truma WiFi — €149.00
→ CampMatic Truma 4G with its own SIM — €189.00
Not sure whether your heater is compatible? Check the help section or send us a short message — we will tell you honestly whether it works for your setup.
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