diff --git a/NmraDcc.cpp b/NmraDcc.cpp
index 9086fef..cf66bdc 100644
--- a/NmraDcc.cpp
+++ b/NmraDcc.cpp
@@ -581,11 +581,14 @@ uint8_t writeCV( unsigned int CV, uint8_t Value)
 {
   switch( CV )
   {
+    case CV_29_CONFIG:
+      // copy addressmode Bit to Flags
+      DccProcState.Flags = ( DccProcState.Flags & ~FLAGS_OUTPUT_ADDRESS_MODE) | (Value & FLAGS_OUTPUT_ADDRESS_MODE);
+      // no break, because myDccAdress must also be reset
     case CV_ACCESSORY_DECODER_ADDRESS_LSB:	// Also same CV for CV_MULTIFUNCTION_PRIMARY_ADDRESS
     case CV_ACCESSORY_DECODER_ADDRESS_MSB:
     case CV_MULTIFUNCTION_EXTENDED_ADDRESS_MSB:
     case CV_MULTIFUNCTION_EXTENDED_ADDRESS_LSB:
-    case CV_29_CONFIG:
 	  DccProcState.myDccAddress = -1;	// Assume any CV Write Operation might change the Address
   }
   
@@ -598,6 +601,10 @@ uint8_t writeCV( unsigned int CV, uint8_t Value)
 
     if( notifyCVChange )
       notifyCVChange( CV, Value) ;
+    if( notifyDccCVChange && !(DccProcState.Flags & FLAGS_SETCV_CALLED) )
+      notifyDccCVChange( CV, Value );
+      
+    DccProcState.Flags &= ~FLAGS_SETCV_CALLED;
   }
   return readEEPROM( CV ) ;
 }
@@ -1323,6 +1330,7 @@ uint8_t NmraDcc::getCV( uint16_t CV )
 ////////////////////////////////////////////////////////////////////////
 uint8_t NmraDcc::setCV( uint16_t CV, uint8_t Value)
 {
+  DccProcState.Flags |= FLAGS_SETCV_CALLED;
   return writeCV(CV,Value);
 }
 
diff --git a/NmraDcc.h b/NmraDcc.h
index 3f74178..2b224e4 100644
--- a/NmraDcc.h
+++ b/NmraDcc.h
@@ -202,6 +202,7 @@ class NmraDcc
 // Flag values to be logically ORed together and passed into the init() method
 #define FLAGS_MY_ADDRESS_ONLY        0x01	// Only process DCC Packets with My Address
 #define FLAGS_AUTO_FACTORY_DEFAULT   0x02	// Call notifyCVResetFactoryDefault() if CV 7 & 8 == 255
+#define FLAGS_SETCV_CALLED           0x10   // only used internally !!
 #define FLAGS_OUTPUT_ADDRESS_MODE    0x40  // CV 29/541 bit 6
 #define FLAGS_DCC_ACCESSORY_DECODER  0x80  // CV 29/541 bit 7
 
@@ -630,6 +631,8 @@ extern uint8_t notifyIsSetCVReady(void) __attribute__ ((weak));
 /*+
  *  notifyCVChange()  Called when a CV value is changed.
  *                    This is called whenever a CV's value is changed.
+ *  notifyDccCVChange()  Called only when a CV value is changed by a Dcc packet or a internal lib function.
+ *                    it is NOT called if the CV is chaged by means of the setCV() method.
  *                    Note: It is not called if notifyCVWrite() is defined
  *                    or if the value in the EEPROM is the same as the value
  *                    in the write command. 
@@ -642,6 +645,7 @@ extern uint8_t notifyIsSetCVReady(void) __attribute__ ((weak));
  *    None
  */
 extern void    notifyCVChange( uint16_t CV, uint8_t Value) __attribute__ ((weak));
+extern void    notifyDccCVChange( uint16_t CV, uint8_t Value) __attribute__ ((weak));
 
 /*+
  *  notifyCVResetFactoryDefault() Called when CVs must be reset.
@@ -654,7 +658,7 @@ extern void    notifyCVChange( uint16_t CV, uint8_t Value) __attribute__ ((weak)
  *
  *  Inputs:
  *    None
- *                                                                                                                                                                                                                                                                                                                                                                                     *
+ *                                                                                                        *
  *  Returns:
  *    None
  */
@@ -667,11 +671,20 @@ extern void    notifyCVResetFactoryDefault(void) __attribute__ ((weak));
  *
  *  Inputs:
  *    None
- *                                                                                                                                                                                                                                                                                                                                                                                     *
+ *                                                                                                        *
  *  Returns:
  *    None
  */
 extern void    notifyCVAck(void) __attribute__ ((weak));
+/*+
+ *  notifyServiceMode(bool) Called when state of 'inServiceMode' changes
+ *
+ *  Inputs:
+ *    bool  state of inServiceMode
+ *                                                                                                      *
+ *  Returns:
+ *    None
+ */
 extern void    notifyServiceMode(bool) __attribute__ ((weak));
 
 // Deprecated, only for backward compatibility with version 1.4.2. Don't use in new designs