# Checking Bluetooth Functionality?

You can check if your radio has the proper Bluetooth functionality using your phone. If it's setup as **Slave/Bluetooth** it will advertise and you can see it via a Bluetooth scanner app. You can see what it's advertising and also connect to it and see the data. When using this normally we want the Head Tracker be sending the information to the radio so you will set your radio to **Master/Bluetooth** (receive mode).

Install an app on your phone called BLE scanner or NRF Connect (Android). Apple should have similar apps. I'm sure there are many others too. Photos shown are on the Taranis 2019 X9D+ SE but other OpenTX radios are similar.

* Under the **Radio->Hardware** page set the **Bluetooth mode** to **Trainer**. (Long press menu to get into the radio setup page, then press Page until your at hardware)
* Under your **Model Setup** page, set the trainer mode as **Slave/Bluetooth**
* Use the scanner app to find the transmitter and connect to it. It will have the name "Hello"
* It will show a list of Services, look for the Service 0xFFF0 and expand it.
* It should show a Characteristic 0xFFF6. Open it
* There should be a button for notify on your phone. Click this button and you will see all the channels data being sent should start with 7E80..... If you move the sticks around you will see the data change. If you see this data it should work.

{% hint style="info" %}
There are two Versions (AFAIK) of the Bluetooth module that FRsky has produced. The most recent goes by the name **PARA**. The older one is just called **Bluetooth Trainer**.\
\
**PARA** is based on the **Texas instruments** **CC2650** chip\
      PARA wireless chips have the part number removed by laser etching. \
**Bluetooth Trainer** is based on the **Texas instruments CC2540** chip\
      Bluetooth trainer shows the CC2540 part number on the chip\
\
If you have the CC2540 chip you will also notice that your phone might pop up with a paring request. The CC2540 sends it data encrypted which is why this happens. There is no authentication (no passwords) it just cannot be sniffed over the air by third parties. No sure why FrSky opted to do this, but they did. The PARA module sends the data un-encrypted.

The older **Bluetooth Trainer** (CC2540) chip is only supported as of Head Tracker V2.0+
{% endhint %}

![](https://1791219135-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-Md5nSb70RWQSfl1nJPs%2F-MduJgG6KCT0EUDIUln3%2F-MduNyd0MQARk_OipdLZ%2FParaCheck.png?alt=media\&token=38f76f7a-a2a4-48e3-9b36-2bf4d10a3cbd)

{% hint style="info" %}
When your in your radio Setup page under Hardware you will notice that you can give your Bluetooth a name. If you have the **PARA** Bluetooth module it doesn't matter what you set here it will advertise as "**Hello**". If you have the CC2540 (Older Bluetooth module) it will show whatever name you have entered in lowercase.\
\
It's not important what you set it to as Head Tracker connects based on the address not name.
{% endhint %}