> For the complete documentation index, see [llms.txt](https://docs.arkelectron.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.arkelectron.com/products/sensor/ark-dist/uart-mavlink.md).

# UART / MAVLink

There is no proprietary raw UART protocol. The UART port streams standard [MAVLink 2](https://mavlink.io/en/).

## Link

| Setting                | Value                              |
| ---------------------- | ---------------------------------- |
| Connector              | **UART** 6-pin JST-GH (not Debug)  |
| Baud                   | 115200 8N1                         |
| Flow control           | Optional RTS/CTS (auto by default) |
| Init sequence          | None — streams after boot          |
| Default sysid / compid | 158 / 158                          |

The Debug connector is NSH console + SWD only.

## Messages

| Message                                                                         | ID  | Rate                 |
| ------------------------------------------------------------------------------- | --- | -------------------- |
| `HEARTBEAT`                                                                     | 0   | 1 Hz                 |
| [`DISTANCE_SENSOR`](https://mavlink.io/en/messages/common.html#DISTANCE_SENSOR) | 132 | One per range sample |

## `DISTANCE_SENSOR` fields

| Field                           | Unit  | Notes                |
| ------------------------------- | ----- | -------------------- |
| `current_distance`              | cm    | `uint16`             |
| `min_distance` / `max_distance` | cm    | `uint16`             |
| `type`                          | enum  | Laser                |
| `orientation`                   | enum  | Default downward     |
| `signal_quality`                | 0–100 | 0 unknown, 1 invalid |

## Rate

UART rate matches the rangefinder sample rate (same data path as DroneCAN): by default 20 Hz on the SR, 15 Hz on the MR and 10 Hz on the LR. See [Node Parameters](/products/sensor/ark-dist/firmware.md#node-parameters).

## Node configuration

No parameters need to be set on the ARK DIST for UART MAVLink output. Stock firmware enables MAVLink on the UART port automatically. The defaults are listed in [Node Parameters](/products/sensor/ark-dist/firmware.md#node-parameters).


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