diff --git a/src/knx/bau091A.cpp b/src/knx/bau091A.cpp
index 5c1bf64..f1ee291 100644
--- a/src/knx/bau091A.cpp
+++ b/src/knx/bau091A.cpp
@@ -18,9 +18,6 @@ Bau091A::Bau091A(Platform& platform)
       _cemiServer(*this)
 #endif
 {
-    // TODO: setup callback for address check on TP1 medium which supports ACK
-    //_dlLayerSecondary.setAckRequiredCallback();
-
     // Before accessing anything of the two router objects they have to be initialized according to the used media combination
     _rtObjPrimary.initialize(1, DptMedium::KNX_IP, true, false, 201);
     _rtObjSecondary.initialize(2, DptMedium::KNX_TP1, false, true, 201);
diff --git a/src/knx/bau2920.cpp b/src/knx/bau2920.cpp
new file mode 100644
index 0000000..3fda0ba
--- /dev/null
+++ b/src/knx/bau2920.cpp
@@ -0,0 +1,149 @@
+#include "config.h"
+#include "bau2920.h"
+#include "bits.h"
+#include <string.h>
+#include <stdio.h>
+
+#if defined(USE_TP) && defined (USE_RF)
+
+using namespace std;
+
+Bau2920::Bau2920(Platform& platform)
+    : BauSystemBCoupler(platform),
+      _rfMediumObject(),
+      _dlLayerPrimary(_deviceObj, _netLayer.getEntity(0), _platform, (ITpUartCallBacks&) *this),
+      _dlLayerSecondary(_deviceObj, _rfMediumObject, _netLayer.getEntity(1), platform)
+#ifdef USE_CEMI_SERVER
+      ,
+      _cemiServer(*this)
+#endif
+{
+    // Before accessing anything of the two router objects they have to be initialized according to the used media combination
+    _rtObjPrimary.initialize(1, DptMedium::KNX_TP1, true, false, 201);
+    _rtObjSecondary.initialize(2, DptMedium::KNX_RF, false, true, 201);
+
+    _netLayer.getEntity(0).dataLinkLayer(_dlLayerPrimary);
+    _netLayer.getEntity(1).dataLinkLayer(_dlLayerSecondary);
+
+#ifdef USE_CEMI_SERVER
+    _cemiServerObject.setMediumTypeAsSupported(DptMedium::KNX_TP1);
+    _cemiServerObject.setMediumTypeAsSupported(DptMedium::KNX_RF);
+    _cemiServer.dataLinkLayer(_dlLayerSecondary); // Secondary I/F is the important one!
+    _dlLayerSecondary.cemiServer(_cemiServer);
+    _memory.addSaveRestore(&_cemiServerObject);
+#endif
+
+    _memory.addSaveRestore(&_rtObjPrimary);
+    _memory.addSaveRestore(&_rtObjSecondary);
+
+    _memory.addSaveRestore(&_rfMediumObject);
+
+    // Set Mask Version in Device Object depending on the BAU
+    _deviceObj.maskVersion(0x2920);
+
+    // Set which interface objects are available in the device object
+    // This differs from BAU to BAU with different medium types.
+    // See PID_IO_LIST
+    Property* prop = _deviceObj.property(PID_IO_LIST);
+    prop->write(1, (uint16_t) OT_DEVICE);
+    prop->write(2, (uint16_t) OT_ROUTER);
+    prop->write(3, (uint16_t) OT_ROUTER);
+    prop->write(3, (uint16_t) OT_APPLICATION_PROG);
+    prop->write(4, (uint16_t) OT_RF_MEDIUM);
+#if defined(USE_DATASECURE) && defined(USE_CEMI_SERVER)
+    prop->write(5, (uint16_t) OT_SECURITY);
+    prop->write(6, (uint16_t) OT_CEMI_SERVER);
+#elif defined(USE_DATASECURE)
+    prop->write(5, (uint16_t) OT_SECURITY);
+#elif defined(USE_CEMI_SERVER)
+    prop->write(5, (uint16_t) OT_CEMI_SERVER);
+#endif
+}
+
+InterfaceObject* Bau2920::getInterfaceObject(uint8_t idx)
+{
+    switch (idx)
+    {
+        case 0:
+            return &_deviceObj;
+        case 1:
+            return &_rtObjPrimary;
+        case 2:
+            return &_rtObjSecondary;
+        case 3:
+            return &_appProgram;
+        case 4:
+            return &_rfMediumObject;
+#if defined(USE_DATASECURE) && defined(USE_CEMI_SERVER)
+        case 5:
+            return &_secIfObj;
+        case 6:
+            return &_cemiServerObject;
+#elif defined(USE_CEMI_SERVER)
+        case 5:
+            return &_cemiServerObject;
+#elif defined(USE_DATASECURE)
+        case 5:
+            return &_secIfObj;
+#endif
+        default:
+            return nullptr;
+    }
+}
+
+InterfaceObject* Bau2920::getInterfaceObject(ObjectType objectType, uint8_t objectInstance)
+{
+    // We do not use it right now. 
+    // Required for coupler mode as there are multiple router objects for example
+    (void) objectInstance;
+
+    switch (objectType)
+    {
+        case OT_DEVICE:
+            return &_deviceObj;
+        case OT_ROUTER:
+            return objectInstance == 0 ? &_rtObjPrimary : &_rtObjSecondary;
+        case OT_APPLICATION_PROG:
+            return &_appProgram;
+        case OT_RF_MEDIUM:
+            return &_rfMediumObject;
+#ifdef USE_DATASECURE
+        case OT_SECURITY:
+            return &_secIfObj;
+#endif
+#ifdef USE_CEMI_SERVER
+        case OT_CEMI_SERVER:
+            return &_cemiServerObject;
+#endif
+        default:
+            return nullptr;
+    }
+}
+
+void Bau2920::doMasterReset(EraseCode eraseCode, uint8_t channel)
+{
+    // Common SystemB objects
+    BauSystemBCoupler::doMasterReset(eraseCode, channel);
+
+    _rfMediumObject.masterReset(eraseCode, channel);
+}
+
+bool Bau2920::enabled()
+{
+    return _dlLayerPrimary.enabled() && _dlLayerSecondary.enabled();
+}
+
+void Bau2920::enabled(bool value)
+{
+    _dlLayerPrimary.enabled(value);
+    _dlLayerSecondary.enabled(value);
+}
+
+void Bau2920::loop()
+{
+    _dlLayerPrimary.loop();
+    _dlLayerSecondary.loop();
+    BauSystemBCoupler::loop();
+}
+
+#endif
diff --git a/src/knx/bau2920.h b/src/knx/bau2920.h
new file mode 100644
index 0000000..9b8a029
--- /dev/null
+++ b/src/knx/bau2920.h
@@ -0,0 +1,34 @@
+#pragma once
+
+#include "config.h"
+#if defined(USE_TP) && defined (USE_RF)
+#include "bau_systemB_coupler.h"
+#include "tpuart_data_link_layer.h"
+#include "rf_physical_layer.h"
+#include "rf_data_link_layer.h"
+#include "rf_medium_object.h"
+#include "cemi_server_object.h"
+
+class Bau2920 : public BauSystemBCoupler
+{
+  public:
+    Bau2920(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);
+
+    virtual void doMasterReset(EraseCode eraseCode, uint8_t channel) override;
+  private:
+    RfMediumObject _rfMediumObject;
+    TpUartDataLinkLayer _dlLayerPrimary;
+    RfDataLinkLayer _dlLayerSecondary;
+#ifdef USE_CEMI_SERVER
+    CemiServer _cemiServer;
+    CemiServerObject _cemiServerObject;
+#endif
+};
+#endif
diff --git a/src/knx/bau_systemB_coupler.cpp b/src/knx/bau_systemB_coupler.cpp
index 618ae02..092bfef 100644
--- a/src/knx/bau_systemB_coupler.cpp
+++ b/src/knx/bau_systemB_coupler.cpp
@@ -14,7 +14,7 @@ BauSystemBCoupler::BauSystemBCoupler(Platform& platform) :
     _appLayer(*this),
 #endif
     _transLayer(_appLayer),
-    _netLayer(_deviceObj, _transLayer)
+    _netLayer(_deviceObj, _rtObjPrimary, _rtObjSecondary, _transLayer)
 {
     _appLayer.transportLayer(_transLayer);
     _transLayer.networkLayer(_netLayer);
diff --git a/src/knx/data_link_layer.h b/src/knx/data_link_layer.h
index abcd5d8..479c3d8 100644
--- a/src/knx/data_link_layer.h
+++ b/src/knx/data_link_layer.h
@@ -29,7 +29,7 @@ class DataLinkLayer
     virtual void loop() = 0;
     virtual void enabled(bool value) = 0;
     virtual bool enabled() const = 0;
-    virtual bool isOpenMedium() const = 0;
+    virtual DptMedium mediumType() const = 0;
 
   protected:
     void frameRecieved(CemiFrame& frame);
diff --git a/src/knx/ip_data_link_layer.cpp b/src/knx/ip_data_link_layer.cpp
index 06f0b6d..d2df559 100644
--- a/src/knx/ip_data_link_layer.cpp
+++ b/src/knx/ip_data_link_layer.cpp
@@ -99,9 +99,9 @@ bool IpDataLinkLayer::enabled() const
     return _enabled;
 }
 
-bool IpDataLinkLayer::isOpenMedium() const
+DptMedium IpDataLinkLayer::mediumType() const
 {
-    return false;
+    return DptMedium::KNX_IP;
 }
 
 bool IpDataLinkLayer::sendBytes(uint8_t* bytes, uint16_t length)
diff --git a/src/knx/ip_data_link_layer.h b/src/knx/ip_data_link_layer.h
index 46fee6d..a4a7e68 100644
--- a/src/knx/ip_data_link_layer.h
+++ b/src/knx/ip_data_link_layer.h
@@ -17,7 +17,7 @@ class IpDataLinkLayer : public DataLinkLayer
     void loop();
     void enabled(bool value);
     bool enabled() const;
-    virtual bool isOpenMedium() const override;
+    virtual DptMedium mediumType() const override;
 
   private:
     bool _enabled = false;
diff --git a/src/knx/network_layer.cpp b/src/knx/network_layer.cpp
index a09c3b2..8da6f6c 100644
--- a/src/knx/network_layer.cpp
+++ b/src/knx/network_layer.cpp
@@ -11,18 +11,6 @@ NetworkLayer::NetworkLayer(DeviceObject &deviceObj, TransportLayer& layer) :
     _transportLayer(layer)
 {
     _hopCount = _deviceObj.defaultHopCount();
-
-    if ((_deviceObj.induvidualAddress() & 0x00FF) == 0x00)
-    {
-        if ((_deviceObj.induvidualAddress() & 0x0F00) == 0x0)
-        {
-            // Device is a backbone coupler -> individual address: x.0.0
-        }
-        else
-        {
-            // Device is a line coupler -> individual address: x.y.0
-        }
-    }
 }
 
 uint8_t NetworkLayer::hopCount() const
@@ -49,93 +37,3 @@ bool NetworkLayer::isApciSystemBroadcast(APDU& apdu)
     return false;
 }
 
-void NetworkLayer::dataIndication(AckType ack, AddressType addrType, uint16_t destination, FrameFormat format, NPDU& npdu, Priority priority, uint16_t source)
-{
-    HopCountType hopType = npdu.hopCount() == 7 ? UnlimitedRouting : NetworkLayerParameter;
-
-    // Only for devices which are not a coupler
-    if (addrType == InduvidualAddress && destination != _deviceObj.induvidualAddress())
-        return;
-
-    // TODO: remove. getTSAP() will return 0 later anyway. Get rid of dependency to GAT
-    //if (addrType == GroupAddress && !_groupAddressTable.contains(destination))
-    //    return;
-
-//        if (frame.npdu().octetCount() > 0)
-//        {
-//            _print("-> DLL ");
-//            frame.apdu().printPDU();
-//        }
-
-    if (addrType == InduvidualAddress)
-    {
-        //if (npdu.octetCount() > 0)
-        //{
-        //    print.print("<- NL  ");
-        //    npdu.frame().apdu().printPDU();
-        //}
-        _transportLayer.dataIndividualIndication(destination, hopType, priority, source, npdu.tpdu());
-        return;
-    }
-    // group-address type
-    if (destination != 0)
-    {
-        _transportLayer.dataGroupIndication(destination, hopType, priority, source, npdu.tpdu());
-        return;
-    }
-    // destination == 0
-    _transportLayer.dataBroadcastIndication(hopType, priority, source, npdu.tpdu());
-}
-
-void NetworkLayer::dataConfirm(AckType ack, AddressType addressType, uint16_t destination, FrameFormat format, Priority priority, uint16_t source, NPDU& npdu, bool status)
-{
-    HopCountType hopType = npdu.hopCount() == 7 ? UnlimitedRouting : NetworkLayerParameter;
-    if (addressType == InduvidualAddress)
-    {
-        _transportLayer.dataIndividualConfirm(ack, destination, hopType, priority, npdu.tpdu(), status);
-        return;
-    }
-    // group-address type
-    if (destination != 0)
-    {
-        _transportLayer.dataGroupConfirm(ack, source, destination, hopType, priority, npdu.tpdu(), status);
-        return;
-    }
-    // destination == 0
-    _transportLayer.dataBroadcastConfirm(ack, hopType, priority, npdu.tpdu(), status);
-}
-
-void NetworkLayer::broadcastIndication(AckType ack, FrameFormat format, NPDU& npdu, Priority priority, uint16_t source)
-{
-    HopCountType hopType = npdu.hopCount() == 7 ? UnlimitedRouting : NetworkLayerParameter;
-
-    DataLinkLayer& dlLayer = getEntity(npdu.frame().sourceInterface()).dataLinkLayer();
-
-    // for closed media like TP1 and IP
-    if (!dlLayer.isOpenMedium() && isApciSystemBroadcast(npdu.tpdu().apdu()))
-    {
-        npdu.frame().systemBroadcast(SysBroadcast);
-        _transportLayer.dataSystemBroadcastIndication(hopType, priority, source, npdu.tpdu());
-        return;
-    }
-
-    _transportLayer.dataBroadcastIndication(hopType, priority, source, npdu.tpdu());
-}
-
-void NetworkLayer::broadcastConfirm(AckType ack, FrameFormat format, Priority priority, uint16_t source, NPDU& npdu, bool status)
-{
-    HopCountType hopType = npdu.hopCount() == 7 ? UnlimitedRouting : NetworkLayerParameter;
-    _transportLayer.dataBroadcastConfirm(ack, hopType, priority, npdu.tpdu(), status);
-}
-
-void NetworkLayer::systemBroadcastIndication(AckType ack, FrameFormat format, NPDU& npdu, Priority priority, uint16_t source)
-{
-    HopCountType hopType = npdu.hopCount() == 7 ? UnlimitedRouting : NetworkLayerParameter;
-    _transportLayer.dataSystemBroadcastIndication(hopType, priority, source, npdu.tpdu());
-}
-
-void NetworkLayer::systemBroadcastConfirm(AckType ack, FrameFormat format, Priority priority, uint16_t source, NPDU& npdu, bool status)
-{
-    HopCountType hopType = npdu.hopCount() == 7 ? UnlimitedRouting : NetworkLayerParameter;
-    _transportLayer.dataSystemBroadcastConfirm(ack, hopType, npdu.tpdu(), priority, status);
-}
diff --git a/src/knx/network_layer.h b/src/knx/network_layer.h
index 2e570fd..0467d84 100644
--- a/src/knx/network_layer.h
+++ b/src/knx/network_layer.h
@@ -29,20 +29,20 @@ class NetworkLayer
 
   protected:
     DeviceObject& _deviceObj;
+    TransportLayer& _transportLayer;
 
     // from entities
     virtual void dataIndication(AckType ack, AddressType addType, uint16_t destination, FrameFormat format, NPDU& npdu,
-                                Priority priority, uint16_t source);
+                                Priority priority, uint16_t source) = 0;
     virtual void dataConfirm(AckType ack, AddressType addressType, uint16_t destination, FrameFormat format, Priority priority,
-                             uint16_t source, NPDU& npdu, bool status);
+                             uint16_t source, NPDU& npdu, bool status) = 0;
     virtual void broadcastIndication(AckType ack, FrameFormat format, NPDU& npdu,
-                                     Priority priority, uint16_t source);
-    virtual void broadcastConfirm(AckType ack, FrameFormat format, Priority priority, uint16_t source, NPDU& npdu, bool status);
+                                     Priority priority, uint16_t source) = 0;
+    virtual void broadcastConfirm(AckType ack, FrameFormat format, Priority priority, uint16_t source, NPDU& npdu, bool status) = 0;
     virtual void systemBroadcastIndication(AckType ack, FrameFormat format, NPDU& npdu,
-                                           Priority priority, uint16_t source);
-    virtual void systemBroadcastConfirm(AckType ack, FrameFormat format, Priority priority, uint16_t source, NPDU& npdu, bool status);
+                                           Priority priority, uint16_t source) = 0;
+    virtual void systemBroadcastConfirm(AckType ack, FrameFormat format, Priority priority, uint16_t source, NPDU& npdu, bool status) = 0;
 
   private:
-    TransportLayer& _transportLayer;
     uint8_t _hopCount; // Network Layer Parameter hop_count for the device's own outgoing frames (default value from PID_ROUTING_COUNT)
 };
diff --git a/src/knx/network_layer_coupler.cpp b/src/knx/network_layer_coupler.cpp
index 2fa3d7e..6d4e0e2 100644
--- a/src/knx/network_layer_coupler.cpp
+++ b/src/knx/network_layer_coupler.cpp
@@ -1,13 +1,30 @@
 #include "network_layer_coupler.h"
 #include "device_object.h"
+#include "router_object.h"
 #include "tpdu.h"
 #include "cemi_frame.h"
 #include "bits.h"
 
-NetworkLayerCoupler::NetworkLayerCoupler(DeviceObject &deviceObj, TransportLayer& layer) :
+NetworkLayerCoupler::NetworkLayerCoupler(DeviceObject &deviceObj,
+                                         RouterObject& rtObjPrimary,
+                                         RouterObject& rtObjSecondary,
+                                         TransportLayer& layer) :
     NetworkLayer(deviceObj, layer),
-    _netLayerEntities { {*this, 0}, {*this, 1} }
+    _netLayerEntities { {*this, 0}, {*this, 1} },
+    _rtObjPrimary(rtObjPrimary),
+    _rtObjSecondary(rtObjSecondary)
 {
+    if ((_deviceObj.induvidualAddress() & 0x00FF) == 0x00)
+    {
+        if ((_deviceObj.induvidualAddress() & 0x0F00) == 0x0)
+        {
+            // Device is a backbone coupler -> individual address: x.0.0
+        }
+        else
+        {
+            // Device is a line coupler -> individual address: x.y.0
+        }
+    }
 }
 
 NetworkLayerEntity& NetworkLayerCoupler::getEntity(uint8_t interfaceIndex)
@@ -17,47 +34,86 @@ NetworkLayerEntity& NetworkLayerCoupler::getEntity(uint8_t interfaceIndex)
 
 void NetworkLayerCoupler::dataIndication(AckType ack, AddressType addrType, uint16_t destination, FrameFormat format, NPDU& npdu, Priority priority, uint16_t source)
 {
+    HopCountType hopType = npdu.hopCount() == 7 ? UnlimitedRouting : NetworkLayerParameter;
+
+    // TODO: implement routing
+
     // Check if received frame is for us, we are a normal device in this case
     if (addrType == InduvidualAddress && destination == _deviceObj.induvidualAddress())
     {
-        NetworkLayer::dataIndication(ack, addrType, destination, format, npdu, priority, source);
-        // Do not process the frame any further
+        _transportLayer.dataIndividualIndication(destination, hopType, priority, source, npdu.tpdu());
+        return;
+    }
+
+    // group-address type
+    if (destination != 0)
+    {
+        _transportLayer.dataGroupIndication(destination, hopType, priority, source, npdu.tpdu());
         return;
     }
 
-    // TODO: implement routing
 }
 
 void NetworkLayerCoupler::dataConfirm(AckType ack, AddressType addrType, uint16_t destination, FrameFormat format, Priority priority, uint16_t source, NPDU& npdu, bool status)
 {
+    HopCountType hopType = npdu.hopCount() == 7 ? UnlimitedRouting : NetworkLayerParameter;
+
     // Check if received frame is an echo from our sent frame, we are a normal device in this case
     if (source == _deviceObj.induvidualAddress())
     {
-        NetworkLayer::dataConfirm(ack, addrType, destination, format, priority, source, npdu, status);
+        if (addrType == InduvidualAddress)
+        {
+            _transportLayer.dataIndividualConfirm(ack, destination, hopType, priority, npdu.tpdu(), status);
+            return;
+        }
+        // group-address type
+        if (destination != 0)
+        {
+            _transportLayer.dataGroupConfirm(ack, source, destination, hopType, priority, npdu.tpdu(), status);
+            return;
+        }
     }
-    // Do not process the frame any further
+
+    // Do not process the frame any further if it was a routed frame sent from network layer
 }
 
 void NetworkLayerCoupler::broadcastIndication(AckType ack, FrameFormat format, NPDU& npdu, Priority priority, uint16_t source)
 {
-    NetworkLayer::broadcastIndication(ack, format, npdu, priority, source);
+    HopCountType hopType = npdu.hopCount() == 7 ? UnlimitedRouting : NetworkLayerParameter;
+
+    uint8_t sourceInterfaceIndex = npdu.frame().sourceInterface();
+    DptMedium mediumType = getEntity(sourceInterfaceIndex).mediumType();
+
+    // for closed media like TP1 and IP
+    if ( ((mediumType == DptMedium::KNX_TP1) || (mediumType == DptMedium::KNX_IP)) &&
+          isApciSystemBroadcast(npdu.tpdu().apdu()))
+    {
+        npdu.frame().systemBroadcast(SysBroadcast);
+        _transportLayer.dataSystemBroadcastIndication(hopType, priority, source, npdu.tpdu());
+        return;
+    }
+
+    _transportLayer.dataBroadcastIndication(hopType, priority, source, npdu.tpdu());
 
     // TODO: implement routing
 }
 
 void NetworkLayerCoupler::broadcastConfirm(AckType ack, FrameFormat format, Priority priority, uint16_t source, NPDU& npdu, bool status)
 {
+    HopCountType hopType = npdu.hopCount() == 7 ? UnlimitedRouting : NetworkLayerParameter;
+
     // Check if received frame is an echo from our sent frame, we are a normal device in this case
     if (source == _deviceObj.induvidualAddress())
     {
-        NetworkLayer::broadcastConfirm(ack, format, priority, source, npdu, status);
+         _transportLayer.dataBroadcastConfirm(ack, hopType, priority, npdu.tpdu(), status);
     }
     // Do not process the frame any further
 }
 
 void NetworkLayerCoupler::systemBroadcastIndication(AckType ack, FrameFormat format, NPDU& npdu, Priority priority, uint16_t source)
 {
-    NetworkLayer::systemBroadcastIndication(ack, format, npdu, priority, source);
+    HopCountType hopType = npdu.hopCount() == 7 ? UnlimitedRouting : NetworkLayerParameter;
+    _transportLayer.dataSystemBroadcastIndication(hopType, priority, source, npdu.tpdu());
 
     // TODO: implement routing
 }
@@ -67,7 +123,8 @@ void NetworkLayerCoupler::systemBroadcastConfirm(AckType ack, FrameFormat format
     // Check if received frame is an echo from our sent frame, we are a normal device in this case
     if (source == _deviceObj.induvidualAddress())
     {
-        NetworkLayer::systemBroadcastConfirm(ack, format, priority, source, npdu, status);
+        HopCountType hopType = npdu.hopCount() == 7 ? UnlimitedRouting : NetworkLayerParameter;
+        _transportLayer.dataSystemBroadcastConfirm(ack, hopType, npdu.tpdu(), priority, status);
     }
     // Do not process the frame any further
 }
diff --git a/src/knx/network_layer_coupler.h b/src/knx/network_layer_coupler.h
index 4efd9b7..eca37c3 100644
--- a/src/knx/network_layer_coupler.h
+++ b/src/knx/network_layer_coupler.h
@@ -8,13 +8,15 @@
 #include "network_layer.h"
 
 class DeviceObject;
+class RouterObject;
 
 class NetworkLayerCoupler : public NetworkLayer
 {
     friend class NetworkLayerEntity;
 
   public:
-    NetworkLayerCoupler(DeviceObject& deviceObj, TransportLayer& layer);
+    NetworkLayerCoupler(DeviceObject& deviceObj, RouterObject& rtObjPrimary,
+                        RouterObject& rtObjSecondary, TransportLayer& layer);
 
     virtual NetworkLayerEntity& getEntity(uint8_t interfaceIndex) override;
 
@@ -39,4 +41,7 @@ class NetworkLayerCoupler : public NetworkLayer
 
     // Support a maximum of two physical interfaces for couplers
     NetworkLayerEntity _netLayerEntities[2];
+
+    RouterObject& _rtObjPrimary;
+    RouterObject& _rtObjSecondary;
 };
diff --git a/src/knx/network_layer_device.cpp b/src/knx/network_layer_device.cpp
index 22b5d8b..e20c475 100644
--- a/src/knx/network_layer_device.cpp
+++ b/src/knx/network_layer_device.cpp
@@ -58,6 +58,10 @@ void NetworkLayerDevice::dataBroadcastRequest(AckType ack, HopCountType hopType,
 
 void NetworkLayerDevice::dataSystemBroadcastRequest(AckType ack, HopCountType hopType, Priority priority, TPDU& tpdu)
 {
+    // for closed media like TP1 and IP
+    bool isClosedMedium = (getEntity(0).mediumType() == DptMedium::KNX_TP1) || (getEntity(0).mediumType() == DptMedium::KNX_IP);
+    SystemBroadcast broadcastType = (isClosedMedium && isApciSystemBroadcast(tpdu.apdu()) ? Broadcast : SysBroadcast);
+
     NPDU& npdu = tpdu.frame().npdu();
 
     if (hopType == UnlimitedRouting)
@@ -65,5 +69,79 @@ void NetworkLayerDevice::dataSystemBroadcastRequest(AckType ack, HopCountType ho
     else
         npdu.hopCount(hopCount());
 
-    _netLayerEntities[0].sendDataRequest(npdu, ack, 0, priority, GroupAddress, SysBroadcast);
+    _netLayerEntities[0].sendDataRequest(npdu, ack, 0, priority, GroupAddress, broadcastType);
+}
+
+void NetworkLayerDevice::dataIndication(AckType ack, AddressType addrType, uint16_t destination, FrameFormat format, NPDU& npdu, Priority priority, uint16_t source)
+{
+    HopCountType hopType = npdu.hopCount() == 7 ? UnlimitedRouting : NetworkLayerParameter;
+
+    if (addrType == InduvidualAddress)
+    {
+        if (destination != _deviceObj.induvidualAddress())
+            return;
+
+        _transportLayer.dataIndividualIndication(destination, hopType, priority, source, npdu.tpdu());
+        return;
+    }
+
+    // group-address type
+    if (destination != 0)
+    {
+        _transportLayer.dataGroupIndication(destination, hopType, priority, source, npdu.tpdu());
+        return;
+    }
+}
+
+void NetworkLayerDevice::dataConfirm(AckType ack, AddressType addressType, uint16_t destination, FrameFormat format, Priority priority, uint16_t source, NPDU& npdu, bool status)
+{
+    HopCountType hopType = npdu.hopCount() == 7 ? UnlimitedRouting : NetworkLayerParameter;
+    if (addressType == InduvidualAddress)
+    {
+        _transportLayer.dataIndividualConfirm(ack, destination, hopType, priority, npdu.tpdu(), status);
+        return;
+    }
+    // group-address type
+    if (destination != 0)
+    {
+        _transportLayer.dataGroupConfirm(ack, source, destination, hopType, priority, npdu.tpdu(), status);
+        return;
+    }
+}
+
+void NetworkLayerDevice::broadcastIndication(AckType ack, FrameFormat format, NPDU& npdu, Priority priority, uint16_t source)
+{
+    HopCountType hopType = npdu.hopCount() == 7 ? UnlimitedRouting : NetworkLayerParameter;
+
+    uint8_t sourceInterfaceIndex = npdu.frame().sourceInterface();
+    DptMedium mediumType = getEntity(sourceInterfaceIndex).mediumType();
+
+    // for closed media like TP1 and IP
+    if ( ((mediumType == DptMedium::KNX_TP1) || (mediumType == DptMedium::KNX_IP)) &&
+          isApciSystemBroadcast(npdu.tpdu().apdu()))
+    {
+        npdu.frame().systemBroadcast(SysBroadcast);
+        _transportLayer.dataSystemBroadcastIndication(hopType, priority, source, npdu.tpdu());
+        return;
+    }
+
+    _transportLayer.dataBroadcastIndication(hopType, priority, source, npdu.tpdu());
+}
+
+void NetworkLayerDevice::broadcastConfirm(AckType ack, FrameFormat format, Priority priority, uint16_t source, NPDU& npdu, bool status)
+{
+    HopCountType hopType = npdu.hopCount() == 7 ? UnlimitedRouting : NetworkLayerParameter;
+    _transportLayer.dataBroadcastConfirm(ack, hopType, priority, npdu.tpdu(), status);
+}
+
+void NetworkLayerDevice::systemBroadcastIndication(AckType ack, FrameFormat format, NPDU& npdu, Priority priority, uint16_t source)
+{
+    HopCountType hopType = npdu.hopCount() == 7 ? UnlimitedRouting : NetworkLayerParameter;
+    _transportLayer.dataSystemBroadcastIndication(hopType, priority, source, npdu.tpdu());
+}
+
+void NetworkLayerDevice::systemBroadcastConfirm(AckType ack, FrameFormat format, Priority priority, uint16_t source, NPDU& npdu, bool status)
+{
+    HopCountType hopType = npdu.hopCount() == 7 ? UnlimitedRouting : NetworkLayerParameter;
+    _transportLayer.dataSystemBroadcastConfirm(ack, hopType, npdu.tpdu(), priority, status);
 }
diff --git a/src/knx/network_layer_device.h b/src/knx/network_layer_device.h
index fe8f620..9d8143e 100644
--- a/src/knx/network_layer_device.h
+++ b/src/knx/network_layer_device.h
@@ -25,6 +25,18 @@ class NetworkLayerDevice : public NetworkLayer
     virtual void dataSystemBroadcastRequest(AckType ack, HopCountType hopType, Priority priority, TPDU& tpdu) override;
 
   private:
-    // Support only physical interface for normal devices
+    // from entities
+    virtual void dataIndication(AckType ack, AddressType addType, uint16_t destination, FrameFormat format, NPDU& npdu,
+                        Priority priority, uint16_t source) override;
+    virtual void dataConfirm(AckType ack, AddressType addrType, uint16_t destination, FrameFormat format, Priority priority,
+                     uint16_t source, NPDU& npdu, bool status) override;
+    virtual void broadcastIndication(AckType ack, FrameFormat format, NPDU& npdu,
+                             Priority priority, uint16_t source) override;
+    virtual void broadcastConfirm(AckType ack, FrameFormat format, Priority priority, uint16_t source, NPDU& npdu, bool status) override;
+    virtual void systemBroadcastIndication(AckType ack, FrameFormat format, NPDU& npdu,
+                                   Priority priority, uint16_t source) override;
+    virtual void systemBroadcastConfirm(AckType ack, FrameFormat format, Priority priority, uint16_t source, NPDU& npdu, bool status) override;
+
+    // Support only a single physical interface for normal devices
     NetworkLayerEntity _netLayerEntities[1];
 };
diff --git a/src/knx/network_layer_entity.cpp b/src/knx/network_layer_entity.cpp
index 0fca763..2367753 100644
--- a/src/knx/network_layer_entity.cpp
+++ b/src/knx/network_layer_entity.cpp
@@ -19,6 +19,11 @@ DataLinkLayer& NetworkLayerEntity::dataLinkLayer()
     return *_dataLinkLayer;
 }
 
+DptMedium NetworkLayerEntity::mediumType() const
+{
+    return _dataLinkLayer->mediumType();
+}
+
 void NetworkLayerEntity::dataIndication(AckType ack, AddressType addrType, uint16_t destination, FrameFormat format, NPDU& npdu, Priority priority, uint16_t source)
 {
     npdu.frame().sourceInterface(_entityIndex);
diff --git a/src/knx/network_layer_entity.h b/src/knx/network_layer_entity.h
index 4071612..f386173 100644
--- a/src/knx/network_layer_entity.h
+++ b/src/knx/network_layer_entity.h
@@ -18,6 +18,8 @@ class NetworkLayerEntity
     void dataLinkLayer(DataLinkLayer& layer);
     DataLinkLayer& dataLinkLayer();
 
+    DptMedium mediumType() const;
+
     // from data link layer
     void dataIndication(AckType ack, AddressType addType, uint16_t destination, FrameFormat format, NPDU& npdu,
                         Priority priority, uint16_t source);
diff --git a/src/knx/rf_data_link_layer.cpp b/src/knx/rf_data_link_layer.cpp
index b8f4930..fb3b3be 100644
--- a/src/knx/rf_data_link_layer.cpp
+++ b/src/knx/rf_data_link_layer.cpp
@@ -269,9 +269,9 @@ bool RfDataLinkLayer::enabled() const
     return _enabled;
 }
 
-bool RfDataLinkLayer::isOpenMedium() const
+DptMedium RfDataLinkLayer::mediumType() const
 {
-    return true;
+    return DptMedium::KNX_RF;
 }
 
 void RfDataLinkLayer::fillRfFrame(CemiFrame& frame, uint8_t* data)
diff --git a/src/knx/rf_data_link_layer.h b/src/knx/rf_data_link_layer.h
index 71902e7..849d12a 100644
--- a/src/knx/rf_data_link_layer.h
+++ b/src/knx/rf_data_link_layer.h
@@ -25,7 +25,7 @@ class RfDataLinkLayer : public DataLinkLayer
     void loop();
     void enabled(bool value);
     bool enabled() const;
-    virtual bool isOpenMedium() const override;
+    virtual DptMedium mediumType() const override;
 
   private:
     bool _enabled = false;
diff --git a/src/knx/tpuart_data_link_layer.cpp b/src/knx/tpuart_data_link_layer.cpp
index 2ce4418..c55ab62 100644
--- a/src/knx/tpuart_data_link_layer.cpp
+++ b/src/knx/tpuart_data_link_layer.cpp
@@ -466,9 +466,9 @@ bool TpUartDataLinkLayer::enabled() const
     return _enabled;
 }
 
-bool TpUartDataLinkLayer::isOpenMedium() const
+DptMedium TpUartDataLinkLayer::mediumType() const
 {
-    return false;
+    return DptMedium::KNX_TP1;
 }
 
 bool TpUartDataLinkLayer::sendSingleFrameByte()
diff --git a/src/knx/tpuart_data_link_layer.h b/src/knx/tpuart_data_link_layer.h
index bc2de7b..74a1d78 100644
--- a/src/knx/tpuart_data_link_layer.h
+++ b/src/knx/tpuart_data_link_layer.h
@@ -27,7 +27,7 @@ class TpUartDataLinkLayer : public DataLinkLayer
     void loop();
     void enabled(bool value);
     bool enabled() const;
-    virtual bool isOpenMedium() const override;
+    virtual DptMedium mediumType() const override;
 
   private:
     bool _enabled = false;