diff --git a/examples/knx-demo/platformio-ci.ini b/examples/knx-demo/platformio-ci.ini
index 6d3c4dc..ebcb842 100644
--- a/examples/knx-demo/platformio-ci.ini
+++ b/examples/knx-demo/platformio-ci.ini
@@ -34,6 +34,7 @@ lib_deps =
   knx
 
 build_flags =
+  -DMASK_VERSION=0x57B0
   -Wno-unknown-pragmas
 
 ;---------------------------------------------------------
@@ -48,4 +49,5 @@ lib_deps =
   knx
 
 build_flags =
+  -DMASK_VERSION=0x57B0
   -Wno-unknown-pragmas
diff --git a/examples/knx-demo/platformio.ini b/examples/knx-demo/platformio.ini
index 94beed3..22b4a60 100644
--- a/examples/knx-demo/platformio.ini
+++ b/examples/knx-demo/platformio.ini
@@ -47,6 +47,7 @@ lib_deps =
   knx
 
 build_flags =
+  -DMASK_VERSION=0x57B0
   -Wno-unknown-pragmas
 
 ;---------------------------------------------------------
@@ -65,4 +66,5 @@ lib_deps =
   knx
 
 build_flags =
+  -DMASK_VERSION=0x57B0
   -Wno-unknown-pragmas
diff --git a/src/knx/cemi_server.cpp b/src/knx/cemi_server.cpp
index 2a9b557..bd9a8b3 100644
--- a/src/knx/cemi_server.cpp
+++ b/src/knx/cemi_server.cpp
@@ -56,10 +56,10 @@ void CemiServer::dataConfirmationToTunnel(CemiFrame& frame)
 
 void CemiServer::dataIndicationToTunnel(CemiFrame& frame)
 {
-    bool isRf = _dataLinkLayer->isOpenMedium();
+    bool isRf = _dataLinkLayer->mediumType() == DptMedium::KNX_RF;
     uint8_t data[frame.dataLength() + (isRf ? 10 : 0)];
 
-    if (_dataLinkLayer->isOpenMedium())
+    if (isRf)
     {
         data[0] = L_data_ind;     // Message Code
         data[1] = 0x0A;           // Total additional info length
@@ -90,7 +90,7 @@ void CemiServer::dataIndicationToTunnel(CemiFrame& frame)
 
 void CemiServer::frameReceived(CemiFrame& frame)
 {
-    bool isRf = _dataLinkLayer->isOpenMedium();
+    bool isRf = _dataLinkLayer->mediumType() == DptMedium::KNX_RF;
 
     switch(frame.messageCode())
     {