bLength:            0x04
    bDescriptorType:    0x24   (CS_INTERFACE)
    bDescriptorSubtype: 0x02   (Abstract Control Management)
    bmCapabilities:     0x06   (Supports Send_Break, Set_Line_Coding, 
                                Set_Control_Line_State, Get_Line_Coding, 
                                and the notification Serial_State)