Index: firmware/App/Modes/ModeStandby.c
===================================================================
diff -u -r79c2105d7ec35f3caeb977f6e2cc1b494853d211 -r50f4b79164155c1bc375dd3ff0e8588f934dc729
--- firmware/App/Modes/ModeStandby.c	(.../ModeStandby.c)	(revision 79c2105d7ec35f3caeb977f6e2cc1b494853d211)
+++ firmware/App/Modes/ModeStandby.c	(.../ModeStandby.c)	(revision 50f4b79164155c1bc375dd3ff0e8588f934dc729)
@@ -23,6 +23,8 @@
 #include "ModeTxParams.h"
 #include "ModeStandby.h"
 #include "OperationModes.h"
+#include "Switches.h"
+#include "SystemCommTD.h"
 
 /**
  *  @addtogroup TDStandbyMode
@@ -71,7 +73,7 @@
 
     // Re-initialize when transitioning to standby mode
     initStandbyMode();
-    initDDInterface();
+    resetDDInterface();
     setCurrentSubState( NO_SUB_STATE );
 
     // Set user alarm recovery actions allowed in this mode
@@ -88,7 +90,7 @@
 //    setValvePosition( H1_VALV, VALVE_POSITION_A_INSERT_EJECT );
 //    setValvePosition( H19, VALVE_POSITION_A_INSERT_EJECT );
 
-//    doorClosedRequired( FALSE, FALSE );             // door no longer required to be closed in standby mode
+//    doorClosedRequired( FALSE );             // door no longer required to be closed in standby mode
 //    syringeDetectionRequired( FALSE );
 
     // Request DD service record and usage information from DD
@@ -182,7 +184,7 @@
 //                {
 //                    syringePumpVerifyForceSensorDACCalibration();
 //                    homingInitiated = FALSE;                        // reset for next time
-//                    doorClosedRequired( FALSE, FALSE );             // door no longer required to be closed in standby mode
+//                    doorClosedRequired( FALSE );                    // door no longer required to be closed in standby mode
 //                    state = STANDBY_WAIT_FOR_TREATMENT_STATE;       // Go to wait for treatment state after above check
 //                }
 //            }
@@ -203,7 +205,7 @@
 static TD_STANDBY_STATE_T handleStandbyModeWaitForTreatmentState( void )
 {
     TD_STANDBY_STATE_T state     = STANDBY_WAIT_FOR_TREATMENT_STATE;
-//    DG_OP_MODE_T dgOperationMode = getDDOpMode();
+    DD_OP_MODE_T ddOperationMode = getDDOpMode();
 
 //    switch ( dgOperationMode )
 //    {
@@ -293,6 +295,16 @@
             {
                 rejReason = REQUEST_REJECT_REASON_NOT_ALLOWED_IN_CURRENT_MODE;
             }
+            // Verify DD is communicating with HD
+            else if ( isDDCommunicating() != TRUE )
+            {
+                rejReason = REQUEST_REJECT_REASON_DD_COMM_LOST;
+            }
+            // Verify DD is not busy
+            else if ( ( DD_MODE_STAN != getDDOpMode() ) || ( DD_STANDBY_MODE_STATE_IDLE != getDDSubMode() ) ) // || ( isDDPOSTPassed() != TRUE ) )
+            {
+                rejReason = REQUEST_REJECT_REASON_DD_NOT_IN_STANDBY_IDLE_STATE;
+            }
             else
             {
                 // If request to start treatment not rejected, set flag to initiate treatment workflow