> 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/smart-meter-modbus-adapters.md).
# Smart Meter Modbus Adapters
Smartstuff Smart Meter Modbus Adapters make data from supported smart meters available locally through Modbus RTU. This documentation covers the current hardware variants, their shared firmware v2 software layer and legacy firmware v1 installations.
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Start by choosing the hardware variant. Connections, power requirements and physical controls differ between adapters; firmware v2 mappings and configuration are shared.
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## Choose your adapter
### D1MC
D1MC DIN-rail adapter.
Choose [D1MC](/p1-modbus-dongle/hardware-variants/hardware-variants/d1mc.md) for a fixed DIN-rail installation, HAN-NVE support, Modbus RTU screw terminals, flexible 5 V power options and software-controlled RS485 termination.
D1MC currently converts DSMR/P1 and HAN-NVE to Modbus RTU. Its physical Linky TIC/S0 interface is present, but Linky software support is planned and not yet available.
### P1 Modbus Pro (NRGD)
P1 Modbus Pro (NRGD).
Choose [P1 Modbus Pro](/p1-modbus-dongle/hardware-variants/hardware-variants/p1-modbus-pro.md) for a compact smart-meter-to-Modbus RTU adapter. NRGD is available as a regular implementation and as an implementation based on ZAP2/NRGDH. The latter also supports HAN-NVE with a HAN (RJ45)-to-RJ12 cable. Check the connection sticker on the dongle because their Modbus `A` and `B` positions differ.
## Hardware and feature matrix
| Feature | P1 Modbus Pro (NRGD) | Din rail adapter (D1MC) |
| ------------------------------------- | -------------------------------------------------------------------------------- | ------------------------------------------- |
| DSMR/P1 input | Available | Available |
| HAN-NVE | Available on the ZAP2/NRGDH-based implementation with a HAN (RJ45)-to-RJ12 cable | Available with adapter cable |
| Linky TIC hardware | Not available | Interface present; software support planned |
| Modbus RTU | Available | Available |
| Software-controlled 120 Ω termination | Not available | Available; enabled by default |
| USB connection | USB-C | USB-C |
| Additional 5 V screw-terminal supply | Not available | Available |
| P1 output | Available | Not available |
| Firmware v2 | Available | Available |
| Firmware v1 | Legacy installations only | Not supported |
The old white P1 Modbus adapter is intentionally excluded from this current-product matrix. It remains documented only where an older installation or [firmware v1](/p1-modbus-dongle/firmware-v1-legacy/firmware-v1.md) requires it.
## Shared firmware
All current adapters use [firmware v2](/p1-modbus-dongle/firmware-v2-current/firmware-v2.md). One firmware image provides selectable register mappings, Modbus RTU settings, local diagnostics and updates through the USB Device Manager. Hardware-dependent settings appear only when the connected adapter supports them.
Register mappings have one canonical shared source: [Firmware v2 register mappings](/p1-modbus-dongle/firmware-v2-current/register-mapping.md).
## Get started
1. [Choose and install the hardware variant](/p1-modbus-dongle/hardware-variants/installation.md).
2. [Connect to the Device Manager](/p1-modbus-dongle/firmware-v2-current/device-manager.md).
3. [Configure the meter source and Modbus RTU settings](/p1-modbus-dongle/firmware-v2-current/configuration.md).
4. Select the required [register mapping](/p1-modbus-dongle/firmware-v2-current/register-mapping.md).