Talk to MTS 3G modem MF192+ via USB in C

#include "stdio.h"
#include "usb.h"
#include "string.h"
#include "iconv.h"

int OpenMyDevice(struct usb_device **device, usb_dev_handle **udev_handle, int VID, int PID)
{
    struct usb_bus *bus;
    struct usb_device *dev;
    usb_dev_handle *udev;

    int isFound = 0;

    usb_init();
    usb_find_busses();
    usb_find_devices();

    for (bus = usb_busses; bus; bus = bus->next)
    {
        for (dev = bus->devices; dev; dev = dev->next)
        {
            udev = usb_open(dev);
            if ( (dev->descriptor.idVendor == VID) & (dev->descriptor.idProduct == PID))
            {
                isFound = 1;
                break;
            }
            else
            {
                if (udev)
                    usb_close(udev);
            }
        }
        if (isFound)
            break;
    }

    *device = dev;
    *udev_handle = udev;

    return isFound;

}
//Buffer to read
#define BUFREAD 64
#define BUFWRITE 512

int main(void)
{
    struct usb_device *dev;
    usb_dev_handle *udev;
    int rc;

    char s[BUFREAD];
    memset( &s, 0, sizeof s );
    char *msg;

    msg = malloc(BUFWRITE);


//Open DEVICE
    if (OpenMyDevice(&dev, &udev, 0x19d2, 0x1217) != 1)
    {
        fprintf(stderr, "Device not found\n");
        exit(1);
    }


//Sets main configuration
    if (usb_set_configuration(udev, 1) != 0) //bConfigurationValue     1
    {
        usb_close(udev);
        fprintf(stderr, "Couldn't set USB active configuration\n");
        exit(-1);
    }
//WRITE TO USB DEVICE
    if (usb_claim_interface(udev, 1) != 0)
    {
        usb_close(udev);
        fprintf(stderr, "Couldn't claim USB interface\n");
        exit(-1);
    }

    if (usb_set_altinterface(udev, 0) != 0)
    {
        usb_close(udev);
        printf("Couldn't alternate USB interface\n");
        exit(-1);
    }

    msg = "AT\r\n";
    int NUM = strlen(msg);
    rc = usb_bulk_write(udev, 0x01, (char *)msg, NUM, 32);
    if (rc < 0)
        fprintf(stderr, "WRITE ERROR\n");
    printf("written: %i bytes\n", rc);

//READ FROM USB DEVICE
//Release previously claimed interface
    if (usb_release_interface(udev, 1) != 0)
    {
        usb_close(udev);
        fprintf(stderr, "Couldn't release USB interface\n");
        exit(-1);
    }

    if (usb_claim_interface(udev, 0) != 0)
    {
        usb_close(udev);
        fprintf(stderr, "Couldn't claim USB interface\n");
        exit(-1);
    }

    if (usb_set_altinterface(udev, 0) != 0)
    {
        usb_close(udev);
        printf("Couldn't alternate USB interface\n");
        exit(-1);
    }

//  usb_interrupt_read usb_bulk_read
    rc = usb_interrupt_read(udev, 0x81, s, BUFREAD, 5);
    if (rc < 0)
        fprintf(stderr, "READ ERROR\n");

    printf("Read from device %i bytes\n", rc);


//CONVERTING ANSWER TO UTF-8
    iconv_t cd;
    cd = iconv_open("UTF-8", "UCS-2");
    char converted[1024];

    size_t k, strsize, t;

    char *IN, *OUT;
    OUT = (char*)converted;
    IN = (char*)s;

    if( cd == (iconv_t)(-1) )
        err( 1, "iconv_open" );

    strsize = strlen(s);
    t = sizeof converted;
    memset( &converted, 0, sizeof converted );

    k = iconv(cd, &IN, &strsize, &OUT, &t);
    iconv_close(cd);



    printf("Message sent to device:%s\n", msg);
    printf("%s\n", "Read data as int");
    int j;
    for (j=0; j<rc; j++)
        printf("%i\n", s[j]);
    printf("Read data as string: %s\n", s);
    printf("%s\n", converted);
    usb_close(udev);

    return 0;
}