diff --git a/src/knx/bau07B0.cpp b/src/knx/bau07B0.cpp
index 010caf1..47c4f34 100644
--- a/src/knx/bau07B0.cpp
+++ b/src/knx/bau07B0.cpp
@@ -27,18 +27,18 @@ Bau07B0::Bau07B0(Platform& platform)
     // This differs from BAU to BAU with different medium types.
     // See PID_IO_LIST
     Property* prop = _deviceObj.property(PID_IO_LIST);
-    prop->write(1, OT_DEVICE);
-    prop->write(2, OT_ADDR_TABLE);
-    prop->write(3, OT_ASSOC_TABLE);
-    prop->write(4, OT_GRP_OBJ_TABLE);
-    prop->write(5, OT_APPLICATION_PROG);
+    prop->write(1, (uint16_t) OT_DEVICE);
+    prop->write(2, (uint16_t) OT_ADDR_TABLE);
+    prop->write(3, (uint16_t) OT_ASSOC_TABLE);
+    prop->write(4, (uint16_t) OT_GRP_OBJ_TABLE);
+    prop->write(5, (uint16_t) OT_APPLICATION_PROG);
 #if defined(USE_DATASECURE) && defined(USE_CEMI_SERVER)
-    prop->write(6, OT_SECURITY);
-    prop->write(7, OT_CEMI_SERVER);
+    prop->write(6, (uint16_t) OT_SECURITY);
+    prop->write(7, (uint16_t) OT_CEMI_SERVER);
 #elif defined(USE_DATASECURE)
-    prop->write(6, OT_SECURITY);
+    prop->write(6, (uint16_t) OT_SECURITY);
 #elif defined(USE_CEMI_SERVER)
-    prop->write(6, OT_CEMI_SERVER);
+    prop->write(6, (uint16_t) OT_CEMI_SERVER);
 #endif
 }
 
diff --git a/src/knx/bau27B0.cpp b/src/knx/bau27B0.cpp
index 38a9a68..2e4c2b4 100644
--- a/src/knx/bau27B0.cpp
+++ b/src/knx/bau27B0.cpp
@@ -35,19 +35,19 @@ Bau27B0::Bau27B0(Platform& platform)
     // This differs from BAU to BAU with different medium types.
     // See PID_IO_LIST
     Property* prop = _deviceObj.property(PID_IO_LIST);
-    prop->write(1, OT_DEVICE);
-    prop->write(2, OT_ADDR_TABLE);
-    prop->write(3, OT_ASSOC_TABLE);
-    prop->write(4, OT_GRP_OBJ_TABLE);
-    prop->write(5, OT_APPLICATION_PROG);
-    prop->write(6, OT_RF_MEDIUM);
+    prop->write(1, (uint16_t) OT_DEVICE);
+    prop->write(2, (uint16_t) OT_ADDR_TABLE);
+    prop->write(3, (uint16_t) OT_ASSOC_TABLE);
+    prop->write(4, (uint16_t) OT_GRP_OBJ_TABLE);
+    prop->write(5, (uint16_t) OT_APPLICATION_PROG);
+    prop->write(6, (uint16_t) OT_RF_MEDIUM);
 #if defined(USE_DATASECURE) && defined(USE_CEMI_SERVER)
-    prop->write(7, OT_SECURITY);
-    prop->write(8, OT_CEMI_SERVER);
+    prop->write(7, (uint16_t) OT_SECURITY);
+    prop->write(8, (uint16_t) OT_CEMI_SERVER);
 #elif defined(USE_DATASECURE)
-    prop->write(7, OT_SECURITY);
+    prop->write(7, (uint16_t) OT_SECURITY);
 #elif defined(USE_CEMI_SERVER)
-    prop->write(7, OT_CEMI_SERVER);
+    prop->write(7, (uint16_t)OT_CEMI_SERVER);
 #endif
 }
 
diff --git a/src/knx/bau57B0.cpp b/src/knx/bau57B0.cpp
index 62fd288..7d2c007 100644
--- a/src/knx/bau57B0.cpp
+++ b/src/knx/bau57B0.cpp
@@ -32,19 +32,19 @@ Bau57B0::Bau57B0(Platform& platform)
     // This differs from BAU to BAU with different medium types.
     // See PID_IO_LIST
     Property* prop = _deviceObj.property(PID_IO_LIST);
-    prop->write(1, OT_DEVICE);
-    prop->write(2, OT_ADDR_TABLE);
-    prop->write(3, OT_ASSOC_TABLE);
-    prop->write(4, OT_GRP_OBJ_TABLE);
-    prop->write(5, OT_APPLICATION_PROG);
-    prop->write(6, OT_IP_PARAMETER);
+    prop->write(1, (uint16_t) OT_DEVICE);
+    prop->write(2, (uint16_t) OT_ADDR_TABLE);
+    prop->write(3, (uint16_t) OT_ASSOC_TABLE);
+    prop->write(4, (uint16_t) OT_GRP_OBJ_TABLE);
+    prop->write(5, (uint16_t) OT_APPLICATION_PROG);
+    prop->write(6, (uint16_t) OT_IP_PARAMETER);
 #if defined(USE_DATASECURE) && defined(USE_CEMI_SERVER)
-    prop->write(7, OT_SECURITY);
-    prop->write(8, OT_CEMI_SERVER);
+    prop->write(7, (uint16_t) OT_SECURITY);
+    prop->write(8, (uint16_t) OT_CEMI_SERVER);
 #elif defined(USE_DATASECURE)
-    prop->write(7, OT_SECURITY);
+    prop->write(7, (uint16_t) OT_SECURITY);
 #elif defined(USE_CEMI_SERVER)
-    prop->write(7, OT_CEMI_SERVER);
+    prop->write(7, (uint16_t) OT_CEMI_SERVER);
 #endif
 }
 
diff --git a/src/knx/bau_systemB.cpp b/src/knx/bau_systemB.cpp
index a1c6ee3..bcba1c1 100644
--- a/src/knx/bau_systemB.cpp
+++ b/src/knx/bau_systemB.cpp
@@ -359,7 +359,10 @@ void BauSystemB::propertyValueReadIndication(Priority priority, HopCountType hop
     if (obj)
     {
         uint8_t elementSize = obj->propertySize((PropertyID)propertyId);
-        size = elementSize * numberOfElements;
+        if (startIndex > 0)
+            size = elementSize * numberOfElements;
+        else
+            size = sizeof(uint16_t); // size of propert array entry 0 which is the size
     }
     else
         elementCount = 0;
@@ -384,7 +387,10 @@ void BauSystemB::propertyValueExtReadIndication(Priority priority, HopCountType
     if (obj)
     {
         uint8_t elementSize = obj->propertySize((PropertyID)propertyId);
-        size = elementSize * numberOfElements;
+        if (startIndex > 0)
+            size = elementSize * numberOfElements;
+        else
+            size = sizeof(uint16_t); // size of propert array entry 0 which is the size
     }
     else
         elementCount = 0;
diff --git a/src/knx/device_object.cpp b/src/knx/device_object.cpp
index e033f7f..0bcb866 100644
--- a/src/knx/device_object.cpp
+++ b/src/knx/device_object.cpp
@@ -23,7 +23,11 @@ DeviceObject::DeviceObject()
             [](DeviceObject* io, uint16_t start, uint8_t count, uint8_t* data) -> uint8_t 
             { 
                 if(start == 0)
+                {
+                    uint16_t currentNoOfElements = 1;
+                    pushWord(currentNoOfElements, data);
                     return 1;
+                }
                 
                 pushByteArray(io->propertyData(PID_SERIAL_NUMBER), 2, data);
                 return 1;
@@ -36,8 +40,12 @@ DeviceObject::DeviceObject()
             [](DeviceObject* io, uint16_t start, uint8_t count, uint8_t* data) -> uint8_t 
             { 
                 if(start == 0)
+                {
+                    uint16_t currentNoOfElements = 1;
+                    pushWord(currentNoOfElements, data);
                     return 1;
-                
+                }
+
                 *data = io->_prgMode;
                 return 1;
             },
@@ -54,7 +62,11 @@ DeviceObject::DeviceObject()
             [](DeviceObject* io, uint16_t start, uint8_t count, uint8_t* data) -> uint8_t 
             { 
                 if(start == 0)
+                {
+                    uint16_t currentNoOfElements = 1;
+                    pushWord(currentNoOfElements, data);
                     return 1;
+                }
 
                 *data = ((io->_ownAddress >> 8) & 0xff);
 
@@ -64,12 +76,16 @@ DeviceObject::DeviceObject()
             [](DeviceObject* io, uint16_t start, uint8_t count, uint8_t* data) -> uint8_t 
             { 
                 if(start == 0)
+                {
+                    uint16_t currentNoOfElements = 1;
+                    pushWord(currentNoOfElements, data);
                     return 1;
+                }
 
                 *data = (io->_ownAddress & 0xff);
                 return 1;
             }),
-        new DataProperty(PID_IO_LIST, false, PDT_UNSIGNED_INT, 1, ReadLv3 | WriteLv0),
+        new DataProperty(PID_IO_LIST, false, PDT_UNSIGNED_INT, 8, ReadLv3 | WriteLv0),
         new DataProperty(PID_HARDWARE_TYPE, true, PDT_GENERIC_06, 1, ReadLv3 | WriteLv3, hardwareType),
         new DataProperty(PID_DEVICE_DESCRIPTOR, false, PDT_GENERIC_02, 1, ReadLv3 | WriteLv0),
 #ifdef USE_RF
diff --git a/src/knx/property.cpp b/src/knx/property.cpp
index a42989f..e9900e1 100644
--- a/src/knx/property.cpp
+++ b/src/knx/property.cpp
@@ -36,26 +36,25 @@ uint8_t Property::ElementSize() const
         case PDT_CONTROL: // is actually 10 if written, but this is always handled with a callback
         case PDT_GENERIC_01:
         case PDT_UNSIGNED_CHAR:
+        case PDT_BITSET8:
+        case PDT_BINARY_INFORMATION: // only 1 bit really
+        case PDT_ENUM8:
+        case PDT_SCALING:
             return 1;
         case PDT_GENERIC_02:
         case PDT_INT:
         case PDT_KNX_FLOAT:
         case PDT_UNSIGNED_INT:
         case PDT_VERSION:
-            return 2;
-        case PDT_ALARM_INFO:
-        case PDT_BINARY_INFORMATION:
         case PDT_BITSET16:
-        case PDT_BITSET8:
+            return 2;
         case PDT_DATE:
-        case PDT_ENUM8:
         case PDT_ESCAPE:
         case PDT_FUNCTION:
         case PDT_GENERIC_03:
         case PDT_NE_FL:
         case PDT_NE_VL:
         case PDT_POLL_GROUP_SETTING:
-        case PDT_SCALING:
         case PDT_TIME:
         case PDT_UTF8:
             return 3;
@@ -68,6 +67,7 @@ uint8_t Property::ElementSize() const
         case PDT_SHORT_CHAR_BLOCK:
             return 5;
         case PDT_GENERIC_06:
+        case PDT_ALARM_INFO:
             return 6;
         case PDT_GENERIC_07:
             return 7;