Check Windows Device Manager for the correct commport.
There are two adapters with the RJ-45 microphone connector. The portable version with the 3.5mm plug to RJ-45 adapter for older F300/F400 radios will not work on the F121's and later radios.
If you have the aplha display F121 radio, the present CS-F121 SW version is 1_7.
Non display F121S radios use CS-F121S SW version 1_6.
COML, Public Safety Communications Consultant, Interoperability Crusader, Firefighter, and Slayer of Dragons (aka Proprietary Systems), K9PKE