diff --git a/src/knx/tpuart_data_link_layer.cpp b/src/knx/tpuart_data_link_layer.cpp
index 50c103c..4b00aee 100644
--- a/src/knx/tpuart_data_link_layer.cpp
+++ b/src/knx/tpuart_data_link_layer.cpp
@@ -266,8 +266,9 @@ void TpUartDataLinkLayer::loop()
                 {
                     uint8_t c = 0x10;
 
-                    // If this is not a nullptr we consider this a device to be a coupler
-                    // TODO: Improve for coupler mode, only ACK according to filter tables
+                    // TODO: Improve for coupler mode. Use callback from bau to check if we are addressed
+                    // The bau knows everything and could either check the address table object (normal device)
+                    // or any filter tables (coupler) to see if we are addressed.
                     if (_groupAddressTable)
                     {
                         //check if individual or group address
@@ -291,10 +292,26 @@ void TpUartDataLinkLayer::loop()
                     else
                     {
                         // TODO: test for only our coupler
+
                         //individual
-                        if (_deviceObject.induvidualAddress() == getWord(buffer + 4))
+                        //check if individual or group address
+                        if ((buffer[6] & 0x80) == 0)
                         {
-                            c |= 0x01;
+                            //individual
+                            if (_deviceObject.induvidualAddress() == getWord(buffer + 4))
+                            {
+                                c |= 0x01;
+                            }
+                        }
+                        else
+                        {
+                            // TODO: test for only our coupler
+
+                            //group
+                            if (getWord(buffer + 4) == 0)
+                            {
+                                c |= 0x01;
+                            }
                         }
                     }