Index: firmware/App/Services/AlarmMgmt.c
===================================================================
diff -u -ra60ec05d359c0d3f014015e9080b6dbcef0fea28 -rffb9960f7b97e71ba78844c60158d344c909db94
--- firmware/App/Services/AlarmMgmt.c	(.../AlarmMgmt.c)	(revision a60ec05d359c0d3f014015e9080b6dbcef0fea28)
+++ firmware/App/Services/AlarmMgmt.c	(.../AlarmMgmt.c)	(revision ffb9960f7b97e71ba78844c60158d344c909db94)
@@ -16,6 +16,8 @@
  *
  **************************************************************************/
 
+#include "mibspi.h"
+
 #include "AlarmLamp.h"
 #include "OperationModes.h"
 #include "SystemCommMessages.h"
@@ -123,6 +125,12 @@
 /// A blank alarm data record for alarms that do not include alarm data when triggered.
 const ALARM_DATA_T blankAlarmData = { ALARM_DATA_TYPE_NONE, 0 };
 
+// pin assignment for backup alarm audio enable
+#define BACKUP_AUDIO_ENABLE_SPI3_PORT_MASK    0x00000001  // (SPI3-CS0 - re-purposed as output GPIO)
+// backup alarm audio enable/disable macros
+#define SET_BACKUP_AUDIO_ENABLE()             {mibspiREG3->PC3 |= BACKUP_AUDIO_ENABLE_SPI3_PORT_MASK;}
+#define CLR_BACKUP_AUDIO_ENABLE()             {mibspiREG3->PC3 &= ~BACKUP_AUDIO_ENABLE_SPI3_PORT_MASK;}
+
 // ********** private data **********
 
 /// interval (in ms) at which to publish alarm status to CAN bus
@@ -167,6 +175,9 @@
     ALARM_PRIORITY_T p;
     ALARM_ID_T a;
 
+    // disable backup audio
+    CLR_BACKUP_AUDIO_ENABLE();
+
     // initialize alarm states and start time stamps
     for ( a = ALARM_ID_NO_ALARM; a < NUM_OF_ALARM_IDS; a++ )
     {