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?
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just send these commands as text.lqs– lqs2013-02-18 09:56:03 +00:00Commented Feb 18, 2013 at 9:56
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Devices are files in *nix. Try just opening the serial port as a file and read/write from/to it.Paulo Scardine– Paulo Scardine2013-02-18 09:56:11 +00:00Commented Feb 18, 2013 at 9:56
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possible duplicate of Serial port reading and writing with CPaulo Scardine– Paulo Scardine2013-02-18 09:57:50 +00:00Commented Feb 18, 2013 at 9:57
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2 Answers
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...
3 Comments
Aquarius_Girl
thanks, I was wondering how does port distinguish between commands and text.
Dane Balia
It's Hayes method for communicating with modems. It distinguishes by format that is the AT command prepended. Check link in answer below about Serial_Programming
Aquarius_Girl
@DaneBalia Thanks for following up.
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/
1 Comment
hlovdal
And to learn a bit more about AT commands, by all means read the V.250 standard, itu.int/rec/T-REC-V.250-200307-I/en.