Hi Mitel, thanks a lot for the information.
It seems that I had some bug on my tests. I rewrote it here and now I can get success answer for many commands.
I also checked the source code you mentioned, and I can see the implementation of AU915 plan, it looks like correct, although the comments at the Region.h (#define DR_xx) file are wrong!
The only command, I try so far, that always return -1 is the getDataRate(). The dataRate(my_DR) command works just fine.
Another curious thing about this protocol is that MKRWAN version of it has some important changes comparing to the original project from ST. Specially the AT commands sintax is different. While the original GET function is achieve by "AT+<cmd_mnemonic>=?", the MKR version is "AT+<cmd_mnemonic>?" without the "=" sign.
So, can you tell me if you can successfully retrieve the current DR, using modem.getDataRate() ?
Thanks again,
Marcio Jr.