diff --git a/src/zm_monitor.h b/src/zm_monitor.h
index 56785405f..5b9a2ce46 100644
--- a/src/zm_monitor.h
+++ b/src/zm_monitor.h
@@ -100,7 +100,7 @@ public:
   } Deinterlace;
 
   typedef enum {
-    UNKNOWN=-1,
+    UNKNOWN,
     IDLE,
     PREALARM,
     ALARM,