> For the complete documentation index, see [llms.txt](https://docs.sky-drones.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.sky-drones.com/avionics/airlink/interfaces.md).

# Interfaces

## Connectors pinout

### Left side

![Left side](/files/-MYqFW-WLv1qeoTOsIHj)

* Power input with voltage & current monitoring
* AI Mission Computer micro SD card
* Flight Controller micro SD card
* AI Mission Computer USB Type-C
* PPM input, SBUS output, RSSI monitor

#### POWER - JST GH SM10B-GHS-TB

<table><thead><tr><th width="150">Pin</th><th width="150">Name</th><th width="150">Voltage level</th><th>Function</th></tr></thead><tbody><tr><td>1</td><td>12V</td><td>+12V</td><td>Main power input</td></tr><tr><td>2</td><td>12V</td><td>+12V</td><td>Main power input</td></tr><tr><td>3</td><td>12V</td><td>+12V</td><td>Main power input</td></tr><tr><td>4</td><td>BAT_CURRENT</td><td>+3.3V</td><td>Battery current monitoring</td></tr><tr><td>5</td><td>BAT_VOLTAGE</td><td>+3.3V</td><td>Battery voltage monitoring</td></tr><tr><td>6</td><td>3V3</td><td>+3.3V</td><td>3.3V output</td></tr><tr><td>7</td><td>PWR_KEY</td><td>+3.3V</td><td>Power key input</td></tr><tr><td>8</td><td>GND</td><td></td><td>Ground</td></tr><tr><td>9</td><td>GND</td><td></td><td>Ground</td></tr><tr><td>10</td><td>GND</td><td></td><td>Ground</td></tr></tbody></table>

#### CPU SD card - microSD

#### CPU USB - USB Type C

#### RC Connector - JST GH SM06B-GHS-TB

<table><thead><tr><th width="150">Pin</th><th width="150">Name</th><th width="150">Voltage level</th><th>Function</th></tr></thead><tbody><tr><td>1</td><td>5V</td><td>+5V</td><td>5V output</td></tr><tr><td>2</td><td>PPM_IN</td><td>+3.3V</td><td>PPM input</td></tr><tr><td>3</td><td>RSSI_IN</td><td>+3.3V</td><td>RSSI input</td></tr><tr><td>4</td><td>FAN_OUT</td><td>+5V</td><td>Fan output</td></tr><tr><td>5</td><td>SBUS_OUT</td><td>+3.3V</td><td>SBUS output</td></tr><tr><td>6</td><td>GND</td><td></td><td>Ground</td></tr></tbody></table>

#### FMU SD card - microSD

### Right side

![Right side](/files/-MYqFjJRFveEjZ8z8-2N)

* Ethernet port with power output
* Telemetry port
* Second GPS port
* Spare I2C / UART port
* Flight controller USB Type-C
* Micro SIM Card
* HDMI input port (payload camera)

#### ETHERNET - JST GH SM08B-GHS-TB

<table><thead><tr><th width="150">Pin</th><th width="150">Name</th><th width="150">Voltage level</th><th>Function</th></tr></thead><tbody><tr><td>1</td><td>5V</td><td>+5V</td><td>Radio module power supply</td></tr><tr><td>2</td><td>5V</td><td>+5V</td><td>Radio module power supply</td></tr><tr><td>3</td><td>ETH_TXP</td><td>+3.3V</td><td>Ethernet transmit positive</td></tr><tr><td>4</td><td>ETH_TXN</td><td>+3.3V</td><td>Ethernet transmit negative</td></tr><tr><td>5</td><td>ETH_RXP</td><td>+3.3V</td><td>Ethernet receive positive</td></tr><tr><td>6</td><td>ETH_RXN</td><td>+3.3V</td><td>Ethernet receive negative</td></tr><tr><td>7</td><td>GND</td><td></td><td>Ground</td></tr><tr><td>8</td><td>GND</td><td></td><td>Ground</td></tr></tbody></table>

{% hint style="info" %}
Ethernet interface is decoupled with capacitors. Ethernet cable should be twisted to reduce EMI noise. Shorter cables are recommended for increased performance and higher bandwidth of the interface.
{% endhint %}

#### TEL3 - JST GH SM06B-GHS-TB

<table><thead><tr><th width="150">Pin</th><th width="150">Name</th><th width="150">Voltage level</th><th>Function</th></tr></thead><tbody><tr><td>1</td><td>5V</td><td>+5V</td><td>Power supply output</td></tr><tr><td>2</td><td>USART2_TX</td><td>+3.3V</td><td>Telemetry 3 TX</td></tr><tr><td>3</td><td>USART2_RX</td><td>+3.3V</td><td>Telemetry 3 RX</td></tr><tr><td>4</td><td>USART2_CTS</td><td>+3.3V</td><td>Telemetry 3 CTS</td></tr><tr><td>5</td><td>USART2_RTS</td><td>+3.3V</td><td>Telemetry 3 RTS</td></tr><tr><td>6</td><td>GND</td><td></td><td>Ground</td></tr></tbody></table>

#### I2C3 / UART4 - JST GH SM06B-GHS-TB

<table><thead><tr><th width="150">Pin</th><th width="150">Name</th><th width="150">Voltage level</th><th>Function</th></tr></thead><tbody><tr><td>1</td><td>5V</td><td>+5V</td><td>Power supply output</td></tr><tr><td>2</td><td>USART4_TX</td><td>+3.3V</td><td>UART 4 TX</td></tr><tr><td>3</td><td>USART4_RX</td><td>+3.3V</td><td>UART 4 RX</td></tr><tr><td>4</td><td>I2C3_SCL</td><td>+3.3V</td><td>I2C3 Clock</td></tr><tr><td>5</td><td>I2C3_SDA</td><td>+3.3V</td><td>I2C3 Data</td></tr><tr><td>6</td><td>GND</td><td></td><td>Ground</td></tr></tbody></table>

#### GPS2 - JST GH SM06B-GHS-TB

<table><thead><tr><th width="150">Pin</th><th width="150">Name</th><th width="150">Voltage level</th><th>Function</th></tr></thead><tbody><tr><td>1</td><td>5V</td><td>+5V</td><td>Power supply output</td></tr><tr><td>2</td><td>USART8_TX</td><td>+3.3V</td><td>UART 8 TX GPS2</td></tr><tr><td>3</td><td>USART8_RX</td><td>+3.3V</td><td>UART 8 RX GPS2</td></tr><tr><td>4</td><td>I2C2_SCL</td><td>+3.3V</td><td>I2C2 Clock</td></tr><tr><td>5</td><td>I2C2_SDA</td><td>+3.3V</td><td>I2C2 Data</td></tr><tr><td>6</td><td>GND</td><td></td><td>Ground</td></tr></tbody></table>

{% hint style="info" %}
AIRLink has integrated 1.5KΩ pull-up resistors for all I2C lines. No external pull-up resistors required.&#x20;
{% endhint %}

#### FMU USB - USB Type C

#### SIM Card - micro SIM

#### HDMI - mini HDMI

### Front side

![Front side](/files/-MYqGKNnAYTS7yJWVgux)

* Main GNSS and compass port
* Main telemetry port
* CSI camera input
* CAN 1
* CAN 2

#### TEL1 - JST GH SM06B-GHS-TB

<table><thead><tr><th width="150">Pin</th><th width="150">Name</th><th width="150">Voltage level</th><th>Function</th></tr></thead><tbody><tr><td>1</td><td>5V</td><td>+5V</td><td>Power supply output</td></tr><tr><td>2</td><td>USART7_TX</td><td>+3.3V</td><td>Telemetry 1 TX</td></tr><tr><td>3</td><td>USART7_RX</td><td>+3.3V</td><td>Telemetry 1 RX</td></tr><tr><td>4</td><td>USART7_CTS</td><td>+3.3V</td><td>Telemetry 1 CTS</td></tr><tr><td>5</td><td>USART7_RTS</td><td>+3.3V</td><td>Telemetry 1 RTS</td></tr><tr><td>6</td><td>GND</td><td></td><td>Ground</td></tr></tbody></table>

#### GPS1 - JST GH SM10B-GHS-TB

<table><thead><tr><th width="150">Pin</th><th width="150">Name</th><th width="150">Voltage level</th><th>Function</th></tr></thead><tbody><tr><td>1</td><td>5V</td><td>+5V</td><td>Power supply output</td></tr><tr><td>2</td><td>USART1_TX</td><td>+3.3V</td><td>GPS 1 TX</td></tr><tr><td>3</td><td>USART1_RX</td><td>+3.3V</td><td>GPS 1 RX</td></tr><tr><td>4</td><td>I2C1_SCL</td><td>+3.3V</td><td>MAG 1 Clock</td></tr><tr><td>5</td><td>I2C1_SDA</td><td>+3.3V</td><td>MAG 1 Data</td></tr><tr><td>6</td><td>SAFETY_BTN</td><td>+3.3V</td><td>Safety button</td></tr><tr><td>7</td><td>SAFETY_LED</td><td>+3.3V</td><td>Safety LED</td></tr><tr><td>8</td><td>+3V3</td><td>+3.3V</td><td>3.3V output</td></tr><tr><td>9</td><td>BUZZER</td><td>+5V</td><td>Buzzer output</td></tr><tr><td>10</td><td>GND</td><td></td><td>Ground</td></tr></tbody></table>

#### CAN1 - JST GH SM04B-GHS-TB

<table><thead><tr><th width="150">Pin</th><th width="150">Name</th><th width="150">Voltage level</th><th>Function</th></tr></thead><tbody><tr><td>1</td><td>5V</td><td>+5V</td><td>Power supply output</td></tr><tr><td>2</td><td>CAN1_H</td><td>+5V</td><td>CAN 1 High (120Ω)</td></tr><tr><td>3</td><td>CAN1_L</td><td>+5V</td><td>CAN 1 Low (120Ω)</td></tr><tr><td>4</td><td>GND</td><td></td><td>Ground</td></tr></tbody></table>

#### CAN2 - JST GH SM04B-GHS-TB

<table><thead><tr><th width="150">Pin</th><th width="150">Name</th><th width="150">Voltage level</th><th>Function</th></tr></thead><tbody><tr><td>1</td><td>5V</td><td>+5V</td><td>Power supply output</td></tr><tr><td>2</td><td>CAN2_H</td><td>+5V</td><td>CAN 2 High (120Ω)</td></tr><tr><td>3</td><td>CAN2_L</td><td>+5V</td><td>CAN 2 Low (120Ω)</td></tr><tr><td>4</td><td>GND</td><td></td><td>Ground</td></tr></tbody></table>

{% hint style="info" %}
AIRLink has integrated 120Ω CAN bus termination resistor. To comply with ISO 11898 user the second 120Ω resistor at the other end of the bus.
{% endhint %}

#### CAMERA - FPC 30 pin, 0.5mm pitch

### Rear side

{% tabs %}
{% tab title="4G / LTE Edition" %}

<figure><img src="/files/sM8COIOEL9upPNk86hyP" alt=""><figcaption></figcaption></figure>
{% endtab %}

{% tab title="5G Edition" %}

<figure><img src="/files/NJNapWrQXstzmFBrhrFd" alt=""><figcaption></figcaption></figure>
{% endtab %}
{% endtabs %}

* SBUS input
* 16 PWM output channels
* 2x LTE antenna sockets in 4G, 4x LTE antenna sockets in 5G  &#x20;
* WiFi antenna socket (AP & Station modes)

## Serial ports mapping

SmartAP AIRLink has a large number of serial ports with the following pinout:

<table><thead><tr><th width="150">UART Port</th><th width="150">Path</th><th>Description</th></tr></thead><tbody><tr><td>UART1</td><td>/dev/ttyS0</td><td>GPS 1</td></tr><tr><td>UART2</td><td>/dev/ttyS1</td><td>Telemetry 3</td></tr><tr><td>UART3</td><td>/dev/ttyS2</td><td>Debug console (internal connector)</td></tr><tr><td>UART4</td><td>/dev/ttyS3</td><td>Telemetry 4</td></tr><tr><td>UART5</td><td>/dev/ttyS4</td><td>Telemetry 2 (used internally with Mission Computer)</td></tr><tr><td>UART6</td><td>/dev/ttyS5</td><td>PWM IO Module (used internally)</td></tr><tr><td>UART7</td><td>/dev/ttyS6</td><td>Telemetry 1</td></tr><tr><td>UART8</td><td>/dev/ttyS7</td><td>GPS 2</td></tr></tbody></table>

{% hint style="info" %}
Looking for CAD files? Here they are:
{% endhint %}

{% content-ref url="/pages/-MYKLv4jimCoiD2J-6WM" %}
[CAD Model](/avionics/airlink/cad-model.md)
{% endcontent-ref %}

{% hint style="info" %}
Want to see the detailed full specifications? Here is the PDF datasheet:&#x20;
{% endhint %}

{% file src="/files/vkYimy7c8trUd7QF1ohq" %}
SmartAP AIRLink Datasheet
{% endfile %}