serijski port in gsm

[gdb]

Spesnil sem en programcek, ki naj bi preverjal, ce dobim "OK" odgovor od
modema. Na drugi strani ni navaden modem, ampak je GSM aparat Siemens
M35i.

Problem je v tem, da vedno dobin nazaj "smeti". Prebral sem ze na tone
manualov in FAQ-ov, pa mi zadeva nikakor na zaspila.

Prilagam source, ce bi mi kdo lahko pomagal.

#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <termios.h>

#define OPEN_ERR 1
#define WRITE_ERR 2
#define READ_ERR 3

int main(int argc, char *argv[])
{
  char          devfile[30];
  struct        termios options_new, options_save;
  int           fd;
  int           v_ret, i;
  char          *send_str[50];
  char          ch[2];

  if (argc != 2)
  {
    printf("usage : test_at device !!!\n");
    return 99;
  }

  sprintf(devfile,"%s%s","/dev/ttyS",argv[1]);
  if ((fd = open(devfile, O_RDWR | O_NOCTTY)) < 0) /* | O_NONBLOCK); */
  {
   close(fd);
   return OPEN_ERR;
  }

  tcgetattr(fd, &options_save);
/*  bzero(&options_new, sizeof(options_new)); */

  options_new.c_cflag |= B19200;
  options_new.c_cflag |= CS8;
  options_new.c_cflag |= CLOCAL | CREAD | HUPCL | CRTSCTS;

  options_new.c_lflag = 0;

  cfsetispeed (&options_new, B19200);
  cfsetospeed (&options_new, B19200);

  options_new.c_cc[VTIME] = 10;
  options_new.c_cc[VMIN] = 0;

  tcflush(fd, TCIFLUSH);

  tcsetattr(fd, TCSANOW, &options_new);

  *send_str = "AT\r";
  if (write(fd, &send_str, strlen(*send_str)) < strlen(*send_str))
  {
    tcsetattr(fd, TCSANOW, &options_save);
    close(fd);
    return WRITE_ERR;
  }

  i=0;
  while (read(fd, &ch, 1) > 0)
  {
   i += 1;
   printf("%s", ch);
  }
  tcsetattr(fd, TCSANOW, &options_save);
  close(fd);

  if (i <= 0)
    return READ_ERR;
  else
    return 0;
}


cu