> For the complete documentation index, see [llms.txt](https://docs.smart-stuff.nl/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.smart-stuff.nl/p1-modbus-dongle/introduction.md).

# Introduction

<figure><img src="/files/Xciu7V1pe41moFqKLDSS" alt="P1 Modbus Dongle with terminal connector" width="375"><figcaption></figcaption></figure>

{% hint style="info" %}
From 15 June 2026, all P1 Modbus Dongles are shipped with v2 firmware. The configuration can be viewed and changed via the USB connection and the configuration website: <https://config.smart-stuff.nl/>
{% endhint %}

The documentation is divided into two firmware generations:

* **Firmware v2 (current):** one configurable firmware image with USB Device Manager support.
* **Firmware v1 (legacy):** separate firmware variants with a fixed Modbus mapping and default communication settings. Existing v1 dongles can migrate to v2.

{% content-ref url="/pages/1K58ncfdjBp0CgFjntnG" %}
[Firmware v2 overview](/p1-modbus-dongle/firmware-v2-current/firmware-v2.md)
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{% content-ref url="/pages/kZ6xQupM7UzaZXLIApa1" %}
[Firmware v1 overview](/p1-modbus-dongle/firmware-v1-legacy/firmware-v1.md)
{% endcontent-ref %}

{% hint style="warning" %}
The dongle is made for v5 SMR meters. In The Netherlands v2/v4 meters are common too. Some data is missing in v2 and v4 meters.
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## Why we do this?

Started designing and manufacturing the dongles in 2020. The main reason is an open solution that is affordable without any subscription.

The concept can be summarised in a few words:

* Privacy first: data always belongs to the user and is not shared
* Safe design
* No subscription
* Accessible: in terms of costs and user experience
* Open solution

## Primary functions

The primary functions of the dongle are:

* Power supply from the P1 meter (DSMR version 4/5 only)
* Reading the smart meter (via the p1 connection)
* Sharing the P1 information via Modbus RTU (RS485)

## Quick start

The dongle is ready for use in a few minutes. The steps are:

{% content-ref url="/pages/dJoFlanuRSEaVw5VHDU5" %}
[Installation](/p1-modbus-dongle/getting-started/installation.md)
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{% content-ref url="/pages/DVJWYkzmGza4xPrpOBKo" %}
[Firmware v2 register mappings](/p1-modbus-dongle/firmware-v2-current/register-mapping.md)
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{% content-ref url="/pages/K1hLI89GaO0yVu11o06t" %}
[Release notes](/p1-modbus-dongle/release-notes.md)
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