M0LTE.Ms110d is a .NET implementation of the MIL-STD-188-110D Appendix D 3 kHz HF modem, and ms110d-cpp is a C++ version that is compatible with it on the air. M0LTE.S5066 is a STANAG 5066 Edition 4 HF data link running over the modem, so applications can use the standard SIS interface; its conformance cases are in a separate, language-neutral repository.