diff --git a/DCCEXParser.cpp b/DCCEXParser.cpp
index 530d224..7a61118 100644
--- a/DCCEXParser.cpp
+++ b/DCCEXParser.cpp
@@ -88,7 +88,7 @@ Print *DCCEXParser::stashStream = NULL;
 RingStream *DCCEXParser::stashRingStream = NULL;
 byte DCCEXParser::stashTarget=0;
 
-// This is a JMRI command parser, one instance per incoming stream
+// This is a JMRI command parser.
 // It doesnt know how the string got here, nor how it gets back.
 // It knows nothing about hardware or tracks... it just parses strings and
 // calls the corresponding DCC api.
@@ -159,9 +159,12 @@ int16_t DCCEXParser::splitValues(int16_t result[MAX_COMMAND_PARAMS], const byte
     return parameterCount;
 }
 
-FILTER_CALLBACK DCCEXParser::filterCallback = 0;
+extern __attribute__((weak)) FILTER_CALLBACK myFilter();
+FILTER_CALLBACK DCCEXParser::filterCallback = myFilter;
 FILTER_CALLBACK DCCEXParser::filterRMFTCallback = 0;
 AT_COMMAND_CALLBACK DCCEXParser::atCommandCallback = 0;
+
+// deprecated
 void DCCEXParser::setFilter(FILTER_CALLBACK filter)
 {
     filterCallback = filter;
diff --git a/version.h b/version.h
index 70f913d..c03f77d 100644
--- a/version.h
+++ b/version.h
@@ -12,6 +12,7 @@
 //       Automatic ALIAS(name) 
 //       Command Parser now accepts Underscore in Alias Names
 // 4.0.2 EXRAIL additions:
+//       myFilter automatic detection (no need to call setFilter)
 //       FIX negative route ids in WIthrottle problem. 
 //       IFRED(signal_id), IFAMBER(signal_id), IFGREEN(signal_id)
 //       </RED signal_id> </AMBER signal_id> </GREEN signal_id> commands