diff --git a/wavTrigger.h b/wavTrigger.h
index a89ca72..d949ad8 100644
--- a/wavTrigger.h
+++ b/wavTrigger.h
@@ -33,11 +33,14 @@
 // ==================================================================
 // The following defines are used to control which serial class is
 //  used. Uncomment only the one you wish to use. If all of them are
-//  commented out, the library will use Hardware Serial
-#define __WT_USE_ALTSOFTSERIAL__
+//  commented out, the library will use Software Serial
+
 //#define __WT_USE_SERIAL1__
 //#define __WT_USE_SERIAL2__
 //#define __WT_USE_SERIAL3__
+#if !defined(__WT_USE_SERIAL1__) || !defined(__WT_USE_SERIAL2__) || !defined(__WT_USE_SERIAL3__)
+#define __WT_USE_ALTSOFTSERIAL__
+#endif
 // ==================================================================
 
 #define CMD_GET_VERSION					1