How do I disable the fax functionality on this modem?

AT+FCLASS=0 sets the modem to data mode. By default, this is what should be set already.



Command: +FCLASS= Display Current Fax Class

Values: 0, 1, 2, 8

Default: None

Description:
0 = Data
1 = Fax Class 1, Class 1.0
2 = Fax Class 2, 2.0, 2.1
8 = Voice Commands
10 = Reserved

Note: V.90 Classes: 0,1, 1.0, 2

V.92 Classes: 0, 1, 1.0, 2, 8, 10