Index: firmware/App/Modes/ModeStandby.c
===================================================================
diff -u -rf7b149d8b8c9ea6ac58e4739101693d251d7a355 -rbb114842e73659f097bb8b8ec0d670bfa4f8cb73
--- firmware/App/Modes/ModeStandby.c	(.../ModeStandby.c)	(revision f7b149d8b8c9ea6ac58e4739101693d251d7a355)
+++ firmware/App/Modes/ModeStandby.c	(.../ModeStandby.c)	(revision bb114842e73659f097bb8b8ec0d670bfa4f8cb73)
@@ -223,23 +223,33 @@
 
 /*********************************************************************//**
  * @brief
- * The signalUserStartingTreatment function handles user initiation of a
+ * The signalUserInitiateTreatment function handles user initiation of a
  * treatment.
  * @details Inputs: none
- * @details Outputs: requested mode transition to treatment parameters mode
+ * @details Outputs: treatStartReqReceived
  * @return TRUE if signal accepted, FALSE if not
  *************************************************************************/
-BOOL signalUserStartingTreatment( void )
+BOOL signalUserInitiateTreatment( void )
 {
     BOOL result = FALSE;
+    REQUEST_REJECT_REASON_CODE_T rejReason = REQUEST_REJECT_REASON_NOT_ALLOWED_IN_CURRENT_MODE;
 
     if ( ( MODE_STAN == getCurrentOperationMode() ) && ( STANDBY_WAIT_FOR_TREATMENT_STATE == currentStandbyState ) )
     {
-        treatStartReqReceived = TRUE;
-        result = TRUE;
+        if ( TRUE == isDGCommunicating() )
+        {
+            treatStartReqReceived = TRUE;
+            result = TRUE;
+            rejReason = REQUEST_REJECT_REASON_NONE;
+        }
+        else
+        {
+            rejReason = REQUEST_REJECT_REASON_DG_COMM_LOST;
+        }
     }
-    sendTreatmentStartResponseMsg( result, 0 ); // TODO - provide reason code if rejected
 
+    sendInitiateTreatmentResponseMsg( result, rejReason );
+
     return result;
 }