Index: firmware/App/Services/SystemCommMessages.c
===================================================================
diff -u -rfb714597ad515d3774d69b94808f065788504724 -redd44135869db32d23a0c809f6107b153c34d3bd
--- firmware/App/Services/SystemCommMessages.c	(.../SystemCommMessages.c)	(revision fb714597ad515d3774d69b94808f065788504724)
+++ firmware/App/Services/SystemCommMessages.c	(.../SystemCommMessages.c)	(revision edd44135869db32d23a0c809f6107b153c34d3bd)
@@ -94,6 +94,11 @@
     U32 enableChemicalDisinfect;                            ///< Enable/disable chemical disinfect.
 } HD_INSTITUTIONAL_LOCAL_RECORD_T;
 
+typedef struct
+{
+    U08 topLevelSN[ MAX_TOP_LEVEL_SN_CHARS ];
+} LOCAL_TOP_SN_T;
+
 // ********** private data **********
 
 #ifndef CARTRIDGE_TEST_BUILD
@@ -3335,10 +3340,6 @@
  *************************************************************************/
 void handleHDSerialNumberRequest( void )
 {
-    typedef struct
-    {
-        U08 topLevelSN[ MAX_TOP_LEVEL_SN_CHARS ];
-    } LOCAL_TOP_SN_T;
     MESSAGE_T msg;
     HD_SYSTEM_RECORD_T system;
     U08 i;
@@ -3708,7 +3709,7 @@
     memcpy( payloadPtr, instit, sizeof( HD_INSTITUTIONAL_LOCAL_RECORD_T ) );
 
     // Serialize the message (w/ sync, CRC, and appropriate CAN padding) and add serialized message data to appropriate comm buffer
-    serializeMessage( msg, COMM_BUFFER_OUT_CAN_HD_2_UI, ACK_NOT_REQUIRED );
+    serializeMessage( msg, COMM_BUFFER_OUT_CAN_HD_2_UI, ACK_REQUIRED );
 }
 
 /*********************************************************************//**