diff --git a/src/knx/bau07B0.cpp b/src/knx/bau07B0.cpp
index ce4f056..f6cd0ce 100644
--- a/src/knx/bau07B0.cpp
+++ b/src/knx/bau07B0.cpp
@@ -108,14 +108,20 @@ InterfaceObject* Bau07B0::getInterfaceObject(ObjectType objectType, uint8_t obje
     }
 }
 
-DataLinkLayer& Bau07B0::dataLinkLayer()
+bool Bau07B0::enabled()
 {
-    return _dlLayer;
+    return _dlLayer.enabled();
+}
+
+void Bau07B0::enabled(bool value)
+{
+    _dlLayer.enabled(value);
 }
 
 void Bau07B0::loop()
 {
-    ::BauSystemB::loop();
+    _dlLayer.loop();
+    BauSystemBDevice::loop();
 #ifdef USE_CEMI_SERVER    
     _cemiServer.loop();
 #endif    
diff --git a/src/knx/bau07B0.h b/src/knx/bau07B0.h
index 3e10955..79c7734 100644
--- a/src/knx/bau07B0.h
+++ b/src/knx/bau07B0.h
@@ -12,12 +12,13 @@ class Bau07B0 : public BauSystemBDevice
 {
   public:
     Bau07B0(Platform& platform);
-    void loop();
+    virtual void loop() override;
+    virtual bool enabled() override;
+    virtual void enabled(bool value) override;
     
   protected:
     InterfaceObject* getInterfaceObject(uint8_t idx);
     InterfaceObject* getInterfaceObject(ObjectType objectType, uint8_t objectInstance);
-    DataLinkLayer& dataLinkLayer();
 
   private:
     TpUartDataLinkLayer _dlLayer;
diff --git a/src/knx/bau091A.cpp b/src/knx/bau091A.cpp
index c958bc6..8c70f1e 100644
--- a/src/knx/bau091A.cpp
+++ b/src/knx/bau091A.cpp
@@ -108,14 +108,27 @@ InterfaceObject* Bau091A::getInterfaceObject(ObjectType objectType, uint8_t obje
 void Bau091A::doMasterReset(EraseCode eraseCode, uint8_t channel)
 {
     // Common SystemB objects
-    BauSystemB::doMasterReset(eraseCode, channel);
+    BauSystemBCoupler::doMasterReset(eraseCode, channel);
 
     _ipParameters.masterReset(eraseCode, channel);
 }
 
-DataLinkLayer& Bau091A::dataLinkLayer()
+bool Bau091A::enabled()
 {
-    return _dlLayerSecondary;
+    return _dlLayerPrimary.enabled() && _dlLayerSecondary.enabled();
+}
+
+void Bau091A::enabled(bool value)
+{
+    _dlLayerPrimary.enabled(value);
+    _dlLayerSecondary.enabled(value);
+}
+
+void Bau091A::loop()
+{
+    _dlLayerPrimary.loop();
+    _dlLayerSecondary.loop();
+    BauSystemBCoupler::loop();
 }
 
 #endif
diff --git a/src/knx/bau091A.h b/src/knx/bau091A.h
index 0d1c687..846f0a3 100644
--- a/src/knx/bau091A.h
+++ b/src/knx/bau091A.h
@@ -12,11 +12,13 @@ class Bau091A : public BauSystemBCoupler
 {
   public:
     Bau091A(Platform& platform);
+    virtual void loop() override;
+    virtual bool enabled() override;
+    virtual void enabled(bool value) override;
 
   protected:
     InterfaceObject* getInterfaceObject(uint8_t idx);
     InterfaceObject* getInterfaceObject(ObjectType objectType, uint8_t objectInstance);
-    DataLinkLayer& dataLinkLayer();
 
     virtual void doMasterReset(EraseCode eraseCode, uint8_t channel) override;
   private:
diff --git a/src/knx/bau27B0.cpp b/src/knx/bau27B0.cpp
index 5def14b..46a76b7 100644
--- a/src/knx/bau27B0.cpp
+++ b/src/knx/bau27B0.cpp
@@ -128,14 +128,20 @@ void Bau27B0::doMasterReset(EraseCode eraseCode, uint8_t channel)
     _rfMediumObj.masterReset(eraseCode, channel);
 }
 
-DataLinkLayer& Bau27B0::dataLinkLayer()
+bool Bau27B0::enabled()
 {
-    return _dlLayer;
+    return _dlLayer.enabled();
+}
+
+void Bau27B0::enabled(bool value)
+{
+    _dlLayer.enabled(value);
 }
 
 void Bau27B0::loop()
 {
-    ::BauSystemB::loop();
+    _dlLayer.loop();
+    BauSystemBDevice::loop();
 #ifdef USE_CEMI_SERVER    
     _cemiServer.loop();
 #endif    
diff --git a/src/knx/bau27B0.h b/src/knx/bau27B0.h
index 036d207..80e7cf4 100644
--- a/src/knx/bau27B0.h
+++ b/src/knx/bau27B0.h
@@ -13,12 +13,13 @@ class Bau27B0 : public BauSystemBDevice
 {
   public:
     Bau27B0(Platform& platform);
-    void loop();
+    virtual void loop() override;
+    virtual bool enabled() override;
+    virtual void enabled(bool value) override;
 
   protected:
     InterfaceObject* getInterfaceObject(uint8_t idx);
     InterfaceObject* getInterfaceObject(ObjectType objectType, uint8_t objectInstance);
-    DataLinkLayer& dataLinkLayer();
 
     virtual void doMasterReset(EraseCode eraseCode, uint8_t channel) override;
   private:
diff --git a/src/knx/bau57B0.cpp b/src/knx/bau57B0.cpp
index eb37ef0..485a23a 100644
--- a/src/knx/bau57B0.cpp
+++ b/src/knx/bau57B0.cpp
@@ -124,9 +124,23 @@ void Bau57B0::doMasterReset(EraseCode eraseCode, uint8_t channel)
     _ipParameters.masterReset(eraseCode, channel);
 }
 
-DataLinkLayer& Bau57B0::dataLinkLayer()
+bool Bau57B0::enabled()
 {
-    return _dlLayer;
+    return _dlLayer.enabled();
+}
+
+void Bau57B0::enabled(bool value)
+{
+    _dlLayer.enabled(value);
+}
+
+void Bau57B0::loop()
+{
+    _dlLayer.loop();
+    BauSystemBDevice::loop();
+#ifdef USE_CEMI_SERVER
+    _cemiServer.loop();
+#endif
 }
 
 #endif
diff --git a/src/knx/bau57B0.h b/src/knx/bau57B0.h
index 1066ab7..685526a 100644
--- a/src/knx/bau57B0.h
+++ b/src/knx/bau57B0.h
@@ -11,11 +11,13 @@ class Bau57B0 : public BauSystemBDevice
 {
   public:
     Bau57B0(Platform& platform);
+    virtual void loop() override;
+    virtual bool enabled() override;
+    virtual void enabled(bool value) override;
 
   protected:
     InterfaceObject* getInterfaceObject(uint8_t idx);
     InterfaceObject* getInterfaceObject(ObjectType objectType, uint8_t objectInstance);
-    DataLinkLayer& dataLinkLayer();
 
     virtual void doMasterReset(EraseCode eraseCode, uint8_t channel) override;
   private:
diff --git a/src/knx/bau_systemB.cpp b/src/knx/bau_systemB.cpp
index cedccdc..c3779d0 100644
--- a/src/knx/bau_systemB.cpp
+++ b/src/knx/bau_systemB.cpp
@@ -21,22 +21,6 @@ BauSystemB::BauSystemB(Platform& platform): _memory(platform, _deviceObj),
     _memory.addSaveRestore(&_appProgram);
 }
 
-void BauSystemB::loop()
-{
-    dataLinkLayer().loop();
-    nextRestartState();
-}
-
-bool BauSystemB::enabled()
-{
-    return dataLinkLayer().enabled();
-}
-
-void BauSystemB::enabled(bool value)
-{
-    dataLinkLayer().enabled(value);
-}
-
 void BauSystemB::readMemory()
 {
     _memory.readMemory();
@@ -166,6 +150,7 @@ void BauSystemB::memoryExtReadIndication(Priority priority, HopCountType hopType
 
 void BauSystemB::doMasterReset(EraseCode eraseCode, uint8_t channel)
 {
+    _deviceObj.masterReset(eraseCode, channel);
     _appProgram.masterReset(eraseCode, channel);
 }
 
diff --git a/src/knx/bau_systemB.h b/src/knx/bau_systemB.h
index 7ae6318..4f63638 100644
--- a/src/knx/bau_systemB.h
+++ b/src/knx/bau_systemB.h
@@ -16,13 +16,13 @@ class BauSystemB : protected BusAccessUnit
 {
   public:
     BauSystemB(Platform& platform);
-    virtual void loop();
+    virtual void loop() = 0;
     ApplicationProgramObject& parameters();
     DeviceObject& deviceObject();
     Memory& memory();
     bool configured();
-    bool enabled();
-    void enabled(bool value);
+    virtual bool enabled() = 0;
+    virtual void enabled(bool value) = 0;
     void readMemory();
     void writeMemory();
     void addSaveRestore(SaveRestore* obj);
@@ -37,7 +37,6 @@ class BauSystemB : protected BusAccessUnit
                             uint8_t* data, uint32_t length) override;
 
   protected:
-    virtual DataLinkLayer& dataLinkLayer() = 0;
     virtual ApplicationLayer& applicationLayer() = 0;
 
     void memoryWriteIndication(Priority priority, HopCountType hopType, uint16_t asap, const SecurityControl &secCtrl, uint8_t number,
diff --git a/src/knx/bau_systemB_coupler.cpp b/src/knx/bau_systemB_coupler.cpp
index 0f7c1b5..ac634c2 100644
--- a/src/knx/bau_systemB_coupler.cpp
+++ b/src/knx/bau_systemB_coupler.cpp
@@ -13,9 +13,6 @@ BauSystemBCoupler::BauSystemBCoupler(Platform& platform) :
 #endif
     _transLayer(_appLayer), _netLayer(_deviceObj, _transLayer)
 {
-#ifdef USE_DATASECURE
-    _secIfObj.secureApplicationLayer(_appLayer);
-#endif
     _appLayer.transportLayer(_transLayer);
     _transLayer.networkLayer(_netLayer);
     _memory.addSaveRestore(&_deviceObj);
@@ -33,7 +30,6 @@ ApplicationLayer& BauSystemBCoupler::applicationLayer()
 
 void BauSystemBCoupler::loop()
 {
-    dataLinkLayer().loop();
     _transLayer.loop();
 #ifdef USE_DATASECURE
     _appLayer.loop();
@@ -54,4 +50,5 @@ bool BauSystemBCoupler::configured()
 
 void BauSystemBCoupler::doMasterReset(EraseCode eraseCode, uint8_t channel)
 {
+    BauSystemB::doMasterReset(eraseCode, channel);
 }
diff --git a/src/knx/bau_systemB_coupler.h b/src/knx/bau_systemB_coupler.h
index e7b66dd..4353f3d 100644
--- a/src/knx/bau_systemB_coupler.h
+++ b/src/knx/bau_systemB_coupler.h
@@ -24,10 +24,9 @@ class BauSystemBCoupler : public BauSystemB
     bool configured();
 
   protected:
-    virtual DataLinkLayer& dataLinkLayer() = 0;
     virtual ApplicationLayer& applicationLayer() override;
 
-    virtual void doMasterReset(EraseCode eraseCode, uint8_t channel);
+    virtual void doMasterReset(EraseCode eraseCode, uint8_t channel) override;
 
     enum RestartState
     {
diff --git a/src/knx/bau_systemB_device.cpp b/src/knx/bau_systemB_device.cpp
index 8f7a574..49fb8b7 100644
--- a/src/knx/bau_systemB_device.cpp
+++ b/src/knx/bau_systemB_device.cpp
@@ -14,9 +14,6 @@ BauSystemBDevice::BauSystemBDevice(Platform& platform) :
 #endif
     _transLayer(_appLayer), _netLayer(_deviceObj, _transLayer)
 {
-#ifdef USE_DATASECURE
-    _secIfObj.secureApplicationLayer(_appLayer);
-#endif
     _appLayer.transportLayer(_transLayer);
     _appLayer.associationTableObject(_assocTable);
     _appLayer.groupAddressTable(_addrTable);
@@ -39,7 +36,6 @@ ApplicationLayer& BauSystemBDevice::applicationLayer()
 
 void BauSystemBDevice::loop()
 {
-    dataLinkLayer().loop();
     _transLayer.loop();
     sendNextGroupTelegram();
     nextRestartState();
@@ -138,10 +134,11 @@ bool BauSystemBDevice::configured()
 
 void BauSystemBDevice::doMasterReset(EraseCode eraseCode, uint8_t channel)
 {
+    BauSystemB::doMasterReset(eraseCode, channel);
+
     _addrTable.masterReset(eraseCode, channel);
     _assocTable.masterReset(eraseCode, channel);
     _groupObjTable.masterReset(eraseCode, channel);
-    _appProgram.masterReset(eraseCode, channel);
 #ifdef USE_DATASECURE
     // If erase code is FactoryReset or FactoryResetWithoutIA, set FDSK as toolkey again
     // and disable security mode.
diff --git a/src/knx/bau_systemB_device.h b/src/knx/bau_systemB_device.h
index 29daac6..08ecbbe 100644
--- a/src/knx/bau_systemB_device.h
+++ b/src/knx/bau_systemB_device.h
@@ -22,7 +22,6 @@ class BauSystemBDevice : public BauSystemB
     BauSystemBDevice(Platform& platform);
     virtual void loop();
     GroupObjectTableObject& groupObjectTable();
-    Memory& memory();
     bool configured();
 
   protected:
@@ -40,7 +39,7 @@ class BauSystemBDevice : public BauSystemB
     void sendNextGroupTelegram();
     void updateGroupObject(GroupObject& go, uint8_t* data, uint8_t length);
 
-    virtual void doMasterReset(EraseCode eraseCode, uint8_t channel);
+    virtual void doMasterReset(EraseCode eraseCode, uint8_t channel) override;
 
     AddressTableObject _addrTable;
     AssociationTableObject _assocTable;
diff --git a/src/knx/secure_application_layer.cpp b/src/knx/secure_application_layer.cpp
index ff4901f..69bad03 100644
--- a/src/knx/secure_application_layer.cpp
+++ b/src/knx/secure_application_layer.cpp
@@ -1251,24 +1251,6 @@ bool SecureApplicationLayer::createSecureApdu(APDU& plainApdu, APDU& secureApdu,
     return false;
 }
 
-void SecureApplicationLayer::clearFailureLog()
-{
-    println("clearFailureLog()");
-}
-
-void SecureApplicationLayer::getFailureCounters(uint8_t* data)
-{
-    memset(data, 0, 8);
-    println("getFailureCounters()");
-}
-
-uint8_t SecureApplicationLayer::getFromFailureLogByIndex(uint8_t index, uint8_t* data, uint8_t maxDataLen)
-{
-    print("getFromFailureLogByIndex(): Index: ");
-    println(index);
-    return 0;
-}
-
 uint64_t SecureApplicationLayer::getRandomNumber()
 {
     return 0x000102030405; // TODO: generate random number
diff --git a/src/knx/secure_application_layer.h b/src/knx/secure_application_layer.h
index 0df8f2c..39b5fc5 100644
--- a/src/knx/secure_application_layer.h
+++ b/src/knx/secure_application_layer.h
@@ -32,10 +32,6 @@ class SecureApplicationLayer :  public ApplicationLayer
 
     void groupAddressTable(AddressTableObject& addrTable);
 
-    void clearFailureLog();
-    void getFailureCounters(uint8_t* data);
-    uint8_t getFromFailureLogByIndex(uint8_t index, uint8_t* data, uint8_t maxDataLen);
-
     // from transport layer
     virtual void dataGroupIndication(HopCountType hopType, Priority priority, uint16_t tsap, APDU& apdu) override;
     virtual void dataGroupConfirm(AckType ack, HopCountType hopType, Priority priority, uint16_t tsap,
diff --git a/src/knx/security_interface_object.cpp b/src/knx/security_interface_object.cpp
index 92b67c4..7b07a6d 100644
--- a/src/knx/security_interface_object.cpp
+++ b/src/knx/security_interface_object.cpp
@@ -97,7 +97,7 @@ SecurityInterfaceObject::SecurityInterfaceObject()
                 uint8_t info = data[2];
                 if (id == 0 && info == 0)
                 {
-                    obj->_secAppLayer->clearFailureLog();
+                    obj->clearFailureLog();
                     resultData[0] = ReturnCodes::Success;
                     resultData[1] = id;
                     resultLength = 2;
@@ -123,7 +123,7 @@ SecurityInterfaceObject::SecurityInterfaceObject()
                     resultData[0] = ReturnCodes::Success;
                     resultData[1] = id;
                     resultData[2] = info;
-                    obj->_secAppLayer->getFailureCounters(&resultData[3]); // Put 8 bytes in the buffer
+                    obj->getFailureCounters(&resultData[3]); // Put 8 bytes in the buffer
                     resultLength = 3 + 8;
                     return;
                 }
@@ -132,7 +132,7 @@ SecurityInterfaceObject::SecurityInterfaceObject()
                 {
                     uint8_t maxBufferSize = resultLength; // Remember the maximum buffer size of the buffer that is provided to us
                     uint8_t index = info;
-                    uint8_t numBytes = obj->_secAppLayer->getFromFailureLogByIndex(index, &resultData[2], maxBufferSize);
+                    uint8_t numBytes = obj->getFromFailureLogByIndex(index, &resultData[2], maxBufferSize);
                     if ( numBytes > 0)
                     {
                         resultData[0] = ReturnCodes::Success;
@@ -163,11 +163,6 @@ SecurityInterfaceObject::SecurityInterfaceObject()
     initializeProperties(sizeof(properties), properties);
 }
 
-void SecurityInterfaceObject::secureApplicationLayer(SecureApplicationLayer& secAppLayer)
-{
-    _secAppLayer = &secAppLayer;
-}
-
 uint8_t* SecurityInterfaceObject::save(uint8_t* buffer)
 {
     buffer = pushByte(_state, buffer);
@@ -206,6 +201,24 @@ bool SecurityInterfaceObject::isSecurityModeEnabled()
     return _securityModeEnabled;
 }
 
+void SecurityInterfaceObject::clearFailureLog()
+{
+    println("clearFailureLog()");
+}
+
+void SecurityInterfaceObject::getFailureCounters(uint8_t* data)
+{
+    memset(data, 0, 8);
+    println("getFailureCounters()");
+}
+
+uint8_t SecurityInterfaceObject::getFromFailureLogByIndex(uint8_t index, uint8_t* data, uint8_t maxDataLen)
+{
+    print("getFromFailureLogByIndex(): Index: ");
+    println(index);
+    return 0;
+}
+
 bool SecurityInterfaceObject::isLoaded()
 {
     return _state == LS_LOADED;
diff --git a/src/knx/security_interface_object.h b/src/knx/security_interface_object.h
index 754f2ea..53f5314 100644
--- a/src/knx/security_interface_object.h
+++ b/src/knx/security_interface_object.h
@@ -6,15 +6,11 @@
 #include "interface_object.h"
 #include "knx_types.h"
 
-class SecureApplicationLayer;
-
 class SecurityInterfaceObject: public InterfaceObject
 {
 public:
   SecurityInterfaceObject();
 
-  void secureApplicationLayer(SecureApplicationLayer& secAppLayer);
-
   virtual void masterReset(EraseCode eraseCode, uint8_t channel) override;
 
   bool isSecurityModeEnabled();
@@ -39,10 +35,12 @@ public:
   uint16_t saveSize() override;
 
 private:
-  SecureApplicationLayer* _secAppLayer = nullptr;
-
   void setSecurityMode(bool enabled);
 
+  void clearFailureLog();
+  void getFailureCounters(uint8_t* data);
+  uint8_t getFromFailureLogByIndex(uint8_t index, uint8_t* data, uint8_t maxDataLen);
+
   void errorCode(ErrorCode errorCode);
 
   void loadEvent(const uint8_t* data);