The FSEx is the serie where the last character is determening the frequency range.
- FSEA is 3,3 GHz.
- FSEB is 7 Ghz.
- FSEK is 20 GHz.
- FSEM is 26 GHz.
The number is only for the additional specification. better noise floor etc.
Documentation
The programmer manual can be found here: Part 1 Part 2