// rs232_to_led.c
// e.boelen 5 Mar 2002
// a small c program that will turn pin 4 on a rs232 port 'high'

#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <sys/stat.h>
#include <sys/ioctl.h>

int main(int)
{
  int fd,dtr,i;
  char device[255] = "/dev/ttyS0"; // this is serial port 0 ttyS1 is port1

  fd = open(device, O_RDWR);
  if (fd == -1) {
    char s[255];
    sprintf(s, "statserial: can't open device `%s'", device);
    perror(s);
    exit(1);
  }

  dtr=TIOCM_RTS;
  // Set RTS (pin 4)
  ioctl(fd, TIOCMBIS,&dtr); // low level io function
  sleep(60); // pause for 60 seconds
}