> 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/firmware-v1-legacy/register-mapping.md).

# Firmware v1 register mappings

Firmware v1 uses separately compiled firmware variants. The selected variant determines the mapping and its initial device ID, baud rate and serial format.

{% hint style="warning" %}
This is a legacy reference. Confirm the exact firmware variant installed on the dongle before relying on its mapping or communication defaults.
{% endhint %}

## Native mappings

* [Default P1 mapping](/p1-modbus-dongle/firmware-v1-legacy/register-mapping/default-p1-mapping.md)
* [Default float mapping](/p1-modbus-dongle/firmware-v1-legacy/register-mapping/default-float-mapping.md)

## Meter emulations

* [ABB B21](/p1-modbus-dongle/firmware-v1-legacy/register-mapping/abb-b21.md)
* [DTSU666](/p1-modbus-dongle/firmware-v1-legacy/register-mapping/dtsu666-emulation.md)
* [EM330 / EM340](/p1-modbus-dongle/firmware-v1-legacy/register-mapping/em330-em340-emulation.md)
* [Inepro / KLEFR 6924](/p1-modbus-dongle/firmware-v1-legacy/register-mapping/inepro-klefr-6924-emulation.md)
* [Schneider Charge Pro](/p1-modbus-dongle/firmware-v1-legacy/register-mapping/schneider-charge-pro-emulation.md)
* [SDM630](/p1-modbus-dongle/firmware-v1-legacy/register-mapping/sdm630-emulation.md)

Legacy firmware variants remain available through the [P1 Modbus web installer](https://install.smart-stuff.nl/p1m/). Existing v1 dongles can also [migrate to firmware v2](/p1-modbus-dongle/firmware-v1-legacy/migrate-to-v2.md).