diff --git a/src/knx/bau07B0.cpp b/src/knx/bau07B0.cpp
index 83e6156..9cc10ce 100644
--- a/src/knx/bau07B0.cpp
+++ b/src/knx/bau07B0.cpp
@@ -138,8 +138,8 @@ bool Bau07B0::isAckRequired(uint16_t address, bool isGrpAddr)
         return _addrTable.contains(address);
     }
 
-    // Also ACK for our own individual address or broadcast
-    if (address  == _deviceObj.individualAddress() || address == 0)
+    // Also ACK for our own individual address
+    if (address  == _deviceObj.individualAddress())
         return true;
 
     return false;
diff --git a/src/knx/network_layer_coupler.cpp b/src/knx/network_layer_coupler.cpp
index d54b176..038d455 100644
--- a/src/knx/network_layer_coupler.cpp
+++ b/src/knx/network_layer_coupler.cpp
@@ -98,8 +98,8 @@ bool NetworkLayerCoupler::isRoutedIndividualAddress(uint16_t individualAddress)
     //     This shall serve for protection purposes. (It is useful to prevent all parameterisation in one Subnetwork; the Coupler shall be protected
     //     too. A typical use case is the protection of a Subnetwork that is located outside a building)
 
-    // Also ACK for our own individual address or broadcast
-    if (individualAddress == _deviceObj.individualAddress() || individualAddress == 0)
+    // Also ACK for our own individual address
+    if (individualAddress == _deviceObj.individualAddress())
         return true;
 
     // use 2 for now
diff --git a/src/knx/tpuart_data_link_layer.cpp b/src/knx/tpuart_data_link_layer.cpp
index c56f98f..fe0cb8f 100644
--- a/src/knx/tpuart_data_link_layer.cpp
+++ b/src/knx/tpuart_data_link_layer.cpp
@@ -272,7 +272,7 @@ void TpUartDataLinkLayer::loop()
                     // or any filter tables (coupler) to see if we are addressed.
 
                     //check if individual or group address
-                    bool isGroupAddress = (buffer[6] & 0x80) != 0;
+                    bool isGroupAddress = (buffer[1] & 0x80) != 0;
                     uint16_t addr = getWord(buffer + 4);
 
                     if (_cb.isAckRequired(addr, isGroupAddress))