Index: firmware/App/Services/SystemCommMessages.h
===================================================================
diff -u -re45524455c005d4fa1734efcbaf7ed0499302670 -r4b661aa14eff362b3ebb154e7791fcaa87d68368
--- firmware/App/Services/SystemCommMessages.h	(.../SystemCommMessages.h)	(revision e45524455c005d4fa1734efcbaf7ed0499302670)
+++ firmware/App/Services/SystemCommMessages.h	(.../SystemCommMessages.h)	(revision 4b661aa14eff362b3ebb154e7791fcaa87d68368)
@@ -1,17 +1,17 @@
 /**************************************************************************
 *
-* Copyright (c) 2019-2020 Diality Inc. - All Rights Reserved.
+* Copyright (c) 2019-2021 Diality Inc. - All Rights Reserved.
 *
 * THIS CODE MAY NOT BE COPIED OR REPRODUCED IN ANY FORM, IN PART OR IN
 * WHOLE, WITHOUT THE EXPLICIT PERMISSION OF THE COPYRIGHT OWNER.
 *
-* @file SystemCommMessages.h
+* @file    SystemCommMessages.h
 *
-* @author (last) Sean Nash
-* @date (last) 14-Oct-2020
+* @author  (last)      Sean Nash
+* @date    (last)      19-Aug-2021
 *
-* @author (original) Dara Navaei
-* @date (original) 05-Nov-2019
+* @author  (original)  Dara Navaei
+* @date    (original)  05-Nov-2019
 *
 ***************************************************************************/
 
@@ -23,6 +23,7 @@
 #include "BloodLeak.h"
 #include "BloodPrime.h"
 #include "Bubble.h"
+#include "CommBuffers.h"
 #include "DGInterface.h"
 #include "DialInFlow.h"
 #include "DialOutFlow.h"
@@ -56,7 +57,10 @@
  *  @{
  */
 
-// ********** public definitions **********
+// ********** public definitions **********
+
+#define ACK_REQUIRED                    TRUE                ///< Macro for functions that want to know if an outgoing message requires acknowledgement from receiver.
+#define ACK_NOT_REQUIRED                FALSE               ///< Macro for functions that want to know if an outgoing message requires acknowledgement from receiver.
 
 #define ACK_REQUIRED                    TRUE                ///< Macro for functions that want to know if an outgoing message requires acknowledgement from receiver.
 #define ACK_NOT_REQUIRED                FALSE               ///< Macro for functions that want to know if an outgoing message requires acknowledgement from receiver.
@@ -67,7 +71,10 @@
 U32 serializeMessage( MESSAGE_T msg, COMM_BUFFER_T buffer, BOOL ackReq );
 
 // ACK MSG
-BOOL sendACKMsg( MESSAGE_T *message );
+BOOL sendACKMsg( MESSAGE_T *message );
+
+// Serialize message
+U32 serializeMessage( MESSAGE_T msg, COMM_BUFFER_T buffer, BOOL ackReq );
 
 // MSG_ID_DG_CHECK_IN
 void handleDGCheckIn( MESSAGE_T *message );