> 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

Legacy mapping reference for separately compiled firmware v1 variants.

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).