Hi, The code below reproduces the issue. The code is intentionally kept small, so it deliberately does not have error checking, et al. Now, my concern is that it blocks for the write operation if the cable is disconnected. This is not inline with the /dev/ttyS* operation, for instance. They would not block if I disconnected the serial cable. Is this a bug or feature? :-) If it turns out to be a feature, is it better to use O_NONBLOCK if one does not want to use pthreads, etc? #include <sys/types.h> #include <sys/stat.h> #include <fcntl.h> int main() { const char buf[] = "Hello World!\n"; int fd = open("/dev/ttyGS0", O_RDWR | O_NONBLOCK); int sent = write(fd, buf, sizeof(buf)-1); close(fd); return 0; } Cheers, L. -- To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html