Index: firmware/App/Services/SystemCommMessages.h
===================================================================
diff -u -r07a5add2dff254f7be3699e4efac2b99d3554847 -r6c60d0d0300828750c76f2e397d4e7ccaa84bbb2
--- firmware/App/Services/SystemCommMessages.h	(.../SystemCommMessages.h)	(revision 07a5add2dff254f7be3699e4efac2b99d3554847)
+++ firmware/App/Services/SystemCommMessages.h	(.../SystemCommMessages.h)	(revision 6c60d0d0300828750c76f2e397d4e7ccaa84bbb2)
@@ -72,7 +72,7 @@
 
 // ********** public function prototypes **********
 
-#ifdef ACK_IMPLEMENTED
+#ifndef ACK_NOT_IMPLEMENTED
 // ACK MSG
 BOOL sendACKMsg( MESSAGE_T *message );
 #endif