# Silvus Data Link
## Silvus StreamCaster 4200
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Silvus StreamCaster is supported by AuterionOS 2.2 and later. Please refer to the official StreamCaster 4200 documentation on how to connect and configure the Silvus radios.
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The subsequent documentation requires firmware version v4.X or higher on the Silvus StreamCaster 4200.
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### Configuring the Air Unit
1. Reset the StreamCaster 4200 to factory defaults, check the static IP address of the radio and write it down.
2. Power off the radio and connect the StreamCaster 4200 Ethernet interface to J7 (Ethernet) of Skynode.\ 
3. Set the following environment variables on Skynode. Please refer to [our section about environment variables](https://docs.auterion.com/hardware-integration/auterionos-system-guide/environment-variables) for details about how to change environment variables on Skynode. Once this done power-cycle Skynode to apply the new configuration.
```
PAIRING_MNG_AIR_UNIT_IP=
PAIRING_MNG_IP_PREFIX=172.20
PAIRING_MNG_PAIRING_CHANNEL=2490
PAIRING_MNG_PAIRING_BANDWIDTH=10
PAIRING_MNG_TYPE=SILVUS
PAIRING_MNG_PAIRING_NETWORK_ID=SILVUS
PAIRING_MNG_SIMPLIFIED=1
AP_CONFIGURE_ETHERNET_IP=172.20.110.10
AP_CONFIGURE_ETHERNET_IP_PREFIX=16
```
#### Variables
* **PAIRING\_MNG\_AIR\_UNIT\_IP** has to match the IP address of the Silvus radio used as air unit.
* The following variables can be adjusted for your setup but have to match the configuration in AMC on the ground station:
* **AIRING\_MNG\_PAIRING\_NETWORK\_ID**
* **PAIRING\_MNG\_PAIRING\_CHANNEL**
* **PAIRING\_MNG\_PAIRING\_BANDWIDTH** \\
* **AP\_CONFIGURE\_ETHERNET\_IP** assigns Skynode a static IP address on the Ethernet interface. Note, if you have several Skynodes in the same network, the IP has to be different for each Skynode.
### Configuring the Ground Unit
1. Reset the StreamCaster 4200 used as ground unit to factory defaults.
2. Enable the DHCP server on the StreamCaster 4200 with an address range of 172.20.1.1 to 172.20.1.100 and a netmask of 255.255.0.0.
3. Power-cycle the radio and, if not already done during the configuration, connect the StreamCaster 4200 to the ground station via Ethernet.
4. Open AMC and enable Silvus under **Settings > Silvus.** Enter the IP address of the StreamCaster 4200 used as ground unit into the field **Local IP Address**. Check the **Network ID**, **Channel frequency** and **Channel bandwidth** and adjust them if necessary to match the environment variables on Skynode. Click **Apply** and wait until the ground unit is shown as *Connected*.
### Silvus Pairing
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If you want to use multiple ground stations and vehicles at the same time you have to change the IP addresses or Network ID to separate them within the Silvus radio network.
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After the ground station, Skynode and air unit have been configured and wired they can be paired and then connected. Pairing and connection are managed by Auterion Mission Control.
The steps are:
1. Power Skynode, the air unit, and the ground station Silvus radio. Wait until everything has fully booted.
2. Open Auterion Mission Control in *Fly View* (default).
3. Select the *Pair Vehicle* icon in the top status bar.\
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NOTE: If the pair vehicle icon is not present:
* Select **menu > Settings > Silvus**, and then select the checkbox: **Enable Silvus**.
* Select **menu > Settings > General**, and then select the checkbox: **Use Vehicle Pairing.** The “Pair vehicle” should appear.
4. If no vehicles have previously been paired Mission Control will display the pairing dialog.
5. After approximately one minute pairing should succeed and show a discovered vehicle. In the image below the vehicle is called *skynode*.\ 
6. Press **Pair** to complete the pairing and to connect to the vehicle.\
7. Once the vehicle is connected, Auterion Mission Control will:
* Display the following dialog, press **Done** to finish pairing.\ 
* Display the Skynode as *skynode* in the top bar.\
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When using Skynode together with the Silvus Streamcaster 4200 a simplified pairing process is used which is enabled with the environment variable **PAIRING\_MNG\_SIMPLIFIED**. In this mode the radio is continuously in pairing mode and does not have to be commanded to pair by pressing a button, unlike when using the [Microhard radio](https://docs.auterion.com/hardware-integration/skynode/peripherals/data-link-module).
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