S.Port 1 (upper) – Monitor, receive and set the telemetry data for S6R/S8R receivers (with DIP switch to the upper side)
S.Port 2 (down) - Upgrade S.Port products (with DIP switch to the down side)
How to upgrade S.Port products
Get the Driver and detail instruction Herer: https://www.frsky-rc.com/stk/
Video Here: https://www.frsky-rc.com/how-to-use-frsky-stk-tool-to-update-firmware/
Steps: Put the DIP switch to the down side → connect the USB port of STK to the USB port of PC → run “frsky_update_Sport.exe”, match the COM port number to the one assigned by PC. Click “File” button and select FW version → connect the 3-wire S.Port cable to the S.Port 2 of STK and S.Port of upgraded product → After “device found, please click Download”, then click the “Download” button to start the upgrade → Exit the process by clicking “End” button after “Firmware is updated”.
Learn S6R/ S8R configuration from FrSky website: https://www.frsky-rc.com/how-to-config-frsky-s6r-receiver-with-stk-tool/