You need to check some things.
Seems like could be hardware modem, but not voice.
"Fclass 8" is about voice support, in order to make tone sound, and you got error here.
Please open minicom in a terminal window
Show us a print screen of the result
I hope it goes direct to the modem, but dont know, show us a print screen.
If goes to the modem, do this command:
Then press enter
Print screen again