diff --git a/TODO b/TODO
index 74dc29e..f1bdeae 100644
--- a/TODO
+++ b/TODO
@@ -45,9 +45,6 @@
 
 * Client
 
-- Check the direction
-   The direction provided by the user should be one of the four
-   possible values.
 - Allow to use a string for the direction
    Could be nice, but probably useless.
 
diff --git a/libowlps/owlps.h b/libowlps/owlps.h
index aad0860..170b689 100644
--- a/libowlps/owlps.h
+++ b/libowlps/owlps.h
@@ -62,6 +62,8 @@ typedef enum {FALSE, TRUE} owl_bool ;
 
 /* Direction type */
 enum {NORTH = 1, EAST, SOUTH, WEST} ;
+#define OWL_DIRECTION_MIN 1
+#define OWL_DIRECTION_MAX 4
 typedef uint8_t owl_direction ;
 
 
diff --git a/owlps-client/owlps-client.c b/owlps-client/owlps-client.c
index 8ef709b..89d1e62 100644
--- a/owlps-client/owlps-client.c
+++ b/owlps-client/owlps-client.c
@@ -227,6 +227,16 @@ void check_configuration()
         options.nb_pkt = DEFAULT_NBPKT_NORMAL ;
     }
 
+  // Calibration request but bad direction
+  if (is_calibration_request)
+    if (options.direction < OWL_DIRECTION_MIN ||
+        options.direction > OWL_DIRECTION_MAX)
+      {
+        fprintf(stderr, "Error! « %"PRIu8" » is not a valid"
+                " direction.\n", options.direction) ;
+        exit(ERR_BAD_USAGE) ;
+      }
+
   // Check port numbers
   if (options.dest_port < 1 || options.dest_port > 65535)
     {