diff --git a/examples/sml_server.c b/examples/sml_server.c
index 07a2ae7..cbc88fc 100644
--- a/examples/sml_server.c
+++ b/examples/sml_server.c
@@ -83,7 +83,7 @@ int main(int argc, char **argv) {
 	char *device = "/dev/cu.usbserial";
 	int fd = serial_port_open(device);
 	
-	if (fd < 0) {
+	if (fd > 0) {
 		// listen on the serial device, this call is blocking.
 		sml_transport_listen(fd, &transport_receiver);
 		close(fd);