diff --git a/DCCEXParser.cpp b/DCCEXParser.cpp
index 5dcce10..c6b8fce 100644
--- a/DCCEXParser.cpp
+++ b/DCCEXParser.cpp
@@ -495,7 +495,7 @@ void DCCEXParser::parse(Print *stream, byte *com, RingStream * ringStream)
         if (atCommandCallback && !ringStream) {
           DCCWaveform::mainTrack.setPowerMode(POWERMODE::OFF);
           DCCWaveform::progTrack.setPowerMode(POWERMODE::OFF);
-          atCommandCallback(stream,com);
+          atCommandCallback((HardwareSerial *)stream,com);
           return;
         }
         break;
diff --git a/DCCEXParser.h b/DCCEXParser.h
index f8724fe..8f577a4 100644
--- a/DCCEXParser.h
+++ b/DCCEXParser.h
@@ -23,7 +23,7 @@
 #include "RingStream.h"
 
 typedef void (*FILTER_CALLBACK)(Print * stream, byte & opcode, byte & paramCount, int16_t p[]);
-typedef void (*AT_COMMAND_CALLBACK)(Print * stream,const byte * command);
+typedef void (*AT_COMMAND_CALLBACK)(HardwareSerial * stream,const byte * command);
 
 struct DCCEXParser
 {