> 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-v2-current/configuration.md).

# Configuration

Firmware v2 configuration is shared across Smart Meter Modbus Adapters. The Device Manager identifies the connected hardware and shows only settings supported by that adapter.

Open the [Device Manager](https://config.smart-stuff.nl/), connect with a USB data cable, change the required values and select **Save**.

## Hardware applicability

| Setting                                | P1 Modbus Pro (NRGD)                                                                                                 | D1MC                          |
| -------------------------------------- | -------------------------------------------------------------------------------------------------------------------- | ----------------------------- |
| Smart-meter source                     | Regular NRGD: DSMR/P1 only. ZAP2/NRGDH-based NRGD: DSMR/P1 or HAN-NVE                                                | DSMR/P1 or HAN-NVE            |
| Modbus mapping                         | Available                                                                                                            | Available                     |
| Device ID, baud rate and serial format | Available                                                                                                            | Available                     |
| Software-controlled 120 Ω termination  | Not available                                                                                                        | Available; enabled by default |
| RGB LED brightness                     | Not available on the regular NRGD; shown by the Device Manager when supported on the ZAP2/NRGDH-based implementation | Available                     |
| Modbus monitor                         | Available                                                                                                            | Available                     |

## Smart-meter source

Use **DSMR/P1** for a meter connected directly through the P1 input. On D1MC or the ZAP2/NRGDH-based NRGD, select **HAN-NVE** when a supported HAN-NVE meter is connected through the appropriate adapter cable. The NRGDH-based implementation requires a HAN (RJ45)-to-RJ12 cable.

{% hint style="warning" %}
D1MC's Linky TIC interface is hardware only at this stage. Linky software support is planned and not yet available, so it is not a current meter-source choice.
{% endhint %}

## Modbus communication

Configure the adapter and Modbus master with the same values:

* **Mapping:** the register model expected by the connected system.
* **Device ID:** address used by the Modbus master.
* **Baud rate:** communication speed.
* **Serial format:** data bits, parity and stop bits, such as `8E1`.

The firmware v2 defaults are the Default - TeltoCharge mapping, device ID `43` and `38400 8E1`. Selecting another mapping changes the register model only; it does not automatically change the communication values. See the canonical [register mappings](/p1-modbus-dongle/firmware-v2-current/register-mapping.md) and [confirmed device configurations](/p1-modbus-dongle/firmware-v2-current/confirmed-configurations.md).

## RS485 termination

RS485 termination is a hardware-dependent setting. D1MC includes a software-controlled 120 Ω terminator and ships with it enabled. P1 Modbus Pro (NRGD) does not provide this setting.

Termination is normally used at both physical ends of an RS485 bus, not at every device. Leave D1MC termination enabled when it is at an end and disable it when it is an intermediate node, subject to the design of the complete bus and the connected equipment.

## Status LED brightness

D1MC has an RGB status LED whose brightness can be adjusted in the Device Manager. The ZAP2/NRGDH-based NRGD implementation also has an RGB status LED; the Device Manager shows the brightness setting when that hardware supports it. The regular NRGD uses a mono status LED and does not expose this setting. See [LED indicators](/p1-modbus-dongle/firmware-v2-current/led-indicators.md) for status meanings.

## Modbus monitor and diagnostics

Enable the Modbus monitor during commissioning or troubleshooting. It displays the 30 most recent Modbus RTU requests, including device ID, function code, address, word count and result. It is a local diagnostic view, not permanent logging or analysis software.