# Herelink 1.0 AirUnit to AirUnit instruction

Device required:\
-Airunit x 2 (**\*firmware minimum 20211229 and above**)\
-Ethernet adapter\
-Installing a fan on both airunits to achieve better performance\
<https://docs.cubepilot.org/user-guides/herelink/herelink-faq#herelink-airunit-fan-installation>\
\- usb otg+power cable if ethernet adapter doesn't include a method to power it

![](/files/4WMp7yDzRCPuO50LzYMG)

GroundUnit video out can be accessed via ethernet and MavLink is available as well. Compatible ethernet adapters are shown below:

AX88772 - Ground (not tested Airside)\
[PLUGABLE](https://plugable.com/products/usb2-otge100/) - directly connect to OTG. Nice for the ground side.

AX88179 - Ground and Air\
[UGREEN Ethernet Adapter for Chromecast](https://www.amazon.co.uk/UGREEN-Ethernet-Adaptor-Chromecast-Network/dp/B01N1X28F1/ref=asc_df_B01N1X28F1/?tag=googshopuk-21\&linkCode=df0\&hvadid=309964054975\&hvpos=\&hvnetw=g\&hvrand=13338390534555592071\&hvpone=\&hvptwo=\&hvqmt=\&hvdev=c\&hvdvcmdl=\&hvlocint=\&hvlocphy=9045387\&hvtargid=pla-303357944812\&psc=1) has an additional standard USB to power on airside, cables are quite long however.

R8152 / R8153 - Airside only\
[Cable Matters](https://www.amazon.co.uk/gp/product/B00ET4KHJ2/ref=ppx_yo_dt_b_asin_title_o04_s01?ie=UTF8\&psc=1)

[Anker USB 3.0](https://www.amazon.co.uk/gp/product/B00NPJP33M/ref=ppx_yo_dt_b_asin_title_o04_s00?ie=UTF8\&psc=1) - no blinky lights on the Ethernet port, maybe annoying for debugging

**Note：**\
**-Upgrade both units to the latest firmware before toggling the switches.**\
\&#xNAN;**-Toggle switches both down position as default AirUnit function, firmware only can be upgraded when switches both at down position.**

## 1. GroundUnit and AirUnit Setup

### 1A GroundUnit setup

1. Upgrade AirUnits to the latest firmware.(Make sure toggle both switches at down position)
2. Power off the GroundUnit by disconnecting the power cable (7v-12v).
3. Remove the screws from the chassis.
4. Herelink AirUnit v1.0 (without ethernet port) Toggle the switches as shown below to activate GroundUnit. (1 up, 2 down) \
   **Note: For Herelink AirUnit v1.1 (with ethernet port) GroundUnit activated by toggle switch (1 down, 2up)**
5. Power on GroundUnit by reconnecting the power cable (7v-12v).

![](/files/q3HZrbVr1urURRRtpPKl)

### **1B AirUnit setup**

Upgrade AirUnits to latest firmware.(Make sure toggle both switches down position)

## **2. Pairing**

Press and hold the pairing button for 3s on both AirUnit and GroundUnit within 30s&#x20;

\*Once pairing is completed LED will turn solid GREEN.

<div align="center"><img src="/files/P3A3k3mV2rwG0GM4beBM" alt="1＝Pairing button
2＝Indicator Led"></div>

## 3. AirUnit HDMI functionality

Once AirUnit and GroundUnit are paired, connect the 1080p/720p video source to AirUnit.&#x20;

There are only 1 HDMI port available for communication between AirUnit and GroundUnit, it is marked #3 in the picture below.

![](/files/F8mKf84xtk7CRQJ1cv4v)

## 4. PC setup

1\. Please switch off PC’s WIFI

2\. Go to control panel > Network & Internet > Network connection

3\. Right click and choose properties

4\. Choose “internet (TCP/IPv4)”,then click properties

5\. Click “use the following IP address” and enter 192.168.144.3”

6\. Click “Subnet mask” and it will give you a Subnet mask.

![](/files/QR0dSel8DFkZnyi7Udm7)

## 5. PC video setup

AirUnit video stream can be obtained through VLC, MissionPlanner or QGC

### 5A VLC setup

Go to Media > Open Steaming > Communication Protocol

Copy and paste : “rtsp\://192.168.144.10:8554/H264Video”

Click “Play”.Click “Play”.

![](/files/DvdLRaPY2iHww4W4ZSy4)

### 5B Mission Planner

**Video**

1. Right click the HUD
2. Select ‘Video’
3. Select ‘Set GStreamer Source’
4. Enter “rtspsrc location=rtsp\://192.168.144.10:8554/H264Video latency=1 udp-reconnect=1 timeout=0 do-retransmission=false ! application/x-rtp ! decodebin3 ! queue max-size-buffers=1 leaky=2 ! videoconvert ! video/x-raw,format=BGRx ! appsink name=outsink”
5. Press OK

\
&#x20;**Mavlink**

1. Open Mission Planner
2. Set the port to 'UDPCL' (top right)
3. Click 'Connect'
4. Enter the IP 192.168.144.11
5. Enter port '14552'

### **5C QGC**

Setup(QGC icon at the top-left corner) > Application Settings > General > Fly View > Video Settings > Source > RTSP Video Stream

RTSP URL “rtsp\://192.168.144.10:8554/H264Video”

Go back to the main screen and video input will come out.

![](/files/FslTi4YblJh02CSjqP2P)

## 6. VLC Video Latency Setup

\
VLC latency can be adjusted via below:

Media > Open Network Stream > Network > Click “Show more options” > adjust “caching” time

![](/files/04e18azjPS2WVA6thPWf)

Tool > Preferences > Input / Codecs > Network > Default caching policy > select “Lowest latency”

![](/files/lmnWHI264I4OkmRxpXHI)


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://docs.cubepilot.org/user-guides/herelink/herelink-user-guides/herelink-1.0-airunit-to-airunit-instruction.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.
