Advantech EKI-1121L User Manual page 47

else
{
flag = 1;
cmd = LEDMAN_CMD_OFF;
/*your action*/
}
if( ioctl(devfp, cmd, LEDMAN_HEARTBEAT) < 0
|| ioctl(devfp, cmd, LEDMAN_RESET) < 0 )
{
/*your action*/
}
For a complete example of serial port configuration, please see the provided
lmtest.c example.
41 EKI-1121L/1122L/1124L User Manual