How to send AT commands to serial port through C - Linux

Question

Of course there is termios.h , but here I am talking about AT commands. I want them to get executed .

How to send AT commands to serial port through C in Linux so that they get executed ?

Answer 1

Look at this brief example (it works):

struct termios options;
int fd;

fd = open("/dev/ttyS0", O_RDWR | O_NOCTTY | O_NDELAY);

if (fd < 0)
{
    printf("Error opening serial port\n");
    exit(1);
}

bzero(&options, sizeof(options));
options.c_cflag = B9600 | CS8 | CLOCAL | CREAD | IGNPAR;
tcflush(fd, TCIFLUSH);
tcsetattr(fd, TCSANOW, &options);

if (write(fd, "ATZ\r", 4) < 4)
{
    printf("Write error - %s \n", strerror(errno));
    exit (1);
}

// read back for OK or KO then do your stuff...

Answer 2

Stumbled across this, might help:

http://en.wikibooks.org/wiki/Serial_Programming/Serial_Linux

Also the definitive guide for Advanced Linux Programming in C http://www.advancedlinuxprogramming.com/alp-folder/