---
title: Interface Specifications
description: "Horizon interface specs: USB-C and flight controller connections, MAVLink2 and baud rates, RTS/CTS flow control, UDP passthrough, I/O voltage."
url: "https://docs.somewear.app/unmanned/installer/specifications/interface-specifications/"
updated: "2026-10-22"
requires: {}
facets:
  hardware:
    - horizon:
        since: baseline
  client: []
  satcom: []
---

## Physical interfaces

| **Parameter**               | **Value**                                                                                                                                                |
| --------------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------- |
| GCS computer interface      | USB-C (full-speed USB 2.0); enumerates as 2 virtual serial COM ports                                                                                     |
| Flight controller interface | 12-pin Molex Nano-fit (I/O connector) — see [Hardware Description](https://docs.somewear.app/unmanned/installer/receive/hardware-component-description/) |
| Digital I/O voltage         | 3.3V CMOS (5V tolerant without damage; performance not guaranteed)                                                                                       |

See [Electrical Specifications](https://docs.somewear.app/unmanned/installer/specifications/electrical-specifications/) for the full absolute maximum ratings and recommended operating range behind this figure.

## Protocol configuration

| **Parameter**                             | **Value**        |
| ----------------------------------------- | ---------------- |
| MAVLink baud rate (GCS serial connection) | 57600 bps        |
| Flight controller baud rate (SERIAL1)     | 57600 bps        |
| MAVLink version                           | MAVLink2         |
| Hardware flow control                     | RTS/CTS required |
| UDP passthrough (Beam local)              | 127.0.0.1:14550  |

> **Caution**
>
> The USB-C connector cannot be used to power the Horizon Hardware Unit. Full power must be supplied via the VSUPP and GND pins of the I/O connector.