CrossFire CRSF is protocol designed by Team Blacksheep (TBS) which is supported by all Spirit units except Spirit 1 and micro Spirit. It is for sending all channel data and telemetry at the same time. This mean that you do not have to connect anything else except 4 wires.
There are multiple receivers and satellites with CrossFire CRSF support.
Both cable ends can look like this:
RUD port - direct cable between CRSF RX Ch. Out 1
AIL pin (pin closer to the port label) - wire to CRSF RX Ch. Out 2 signal pin
2 Spirit Settings
Now you are ready to power up the unit. If your Power supply is not connected yet, we recommend to connect it to the AUX1, AUX2 and/or CH0 port. Before you can utilize the CrossFire connection, it is important to set the CrossFire CRSF receiver type in the General tab of the software. Please start the Spirit Settings and change the receiver type as displayed on the photo. Then save the settings (e.g. by CTRL+S) or the Backup tab/Unit - Save and restart the unit.
3 Throttle output
You can connect ESC or Throttle servo directly to the Spirit unit at (AUX/AUX1 port).
4 Radio Integration
Integration support is to be added within following updates.