diff --git a/DCCEXParser.cpp b/DCCEXParser.cpp
index 94b7a66..38bac2f 100644
--- a/DCCEXParser.cpp
+++ b/DCCEXParser.cpp
@@ -550,7 +550,7 @@ void DCCEXParser::parse(Print *stream, byte *com, RingStream * ringStream)
         if (atCommandCallback && !ringStream) {
           DCCWaveform::mainTrack.setPowerMode(POWERMODE::OFF);
           DCCWaveform::progTrack.setPowerMode(POWERMODE::OFF);
-          atCommandCallback(com);
+          atCommandCallback(stream,com);
           return;
         }
         break;
diff --git a/DCCEXParser.h b/DCCEXParser.h
index 3bc94d4..6baeeaa 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)(const byte * command);
+typedef void (*AT_COMMAND_CALLBACK)(Print * stream,const byte * command);
 
 struct DCCEXParser
 {
diff --git a/WifiInterface.cpp b/WifiInterface.cpp
index 3f65cea..6b3e3b8 100644
--- a/WifiInterface.cpp
+++ b/WifiInterface.cpp
@@ -326,25 +326,25 @@ wifiSerialState WifiInterface::setup2(const FSH* SSid, const FSH* password,
 // The sequence "!!!" returns the Arduino to the normal loop mode
 
  
-void WifiInterface::ATCommand(const byte * command) {
+void WifiInterface::ATCommand(HardwareSerial * stream,const byte * command) {
   command++;
   if (*command=='\0') { // User gave <+> command  
-     DIAG(F("ES AT command passthrough mode, use ! to exit"));
-     while(Serial.available()) Serial.read(); // Drain serial input first 
+      stream->print(F("\nES AT command passthrough mode, use ! to exit\n"));
+     while(stream->available()) stream->read(); // Drain serial input first 
      bool startOfLine=true;
      while(true) {
-      while (wifiStream->available()) Serial.write(wifiStream->read());
-      if (Serial.available()) {
-        int cx=Serial.read();
+      while (wifiStream->available()) stream->write(wifiStream->read());
+      if (stream->available()) {
+        int cx=stream->read();
         // A newline followed by !!! is an exit
         if (cx=='\n' || cx=='\r') startOfLine=true; 
         else if (startOfLine && cx=='!')  break;
         else startOfLine=false; 
-        Serial.write(cx);
+        stream->write(cx);
         wifiStream->write(cx);  
        }
      }
-     DIAG(F("Passthrough Ended"));
+     stream->print(F("Passthrough Ended"));
      return; 
   }
   
diff --git a/WifiInterface.h b/WifiInterface.h
index 19f8a3a..8d77ab8 100644
--- a/WifiInterface.h
+++ b/WifiInterface.h
@@ -37,7 +37,7 @@ public:
                           const int port,
                           const byte channel);
   static void loop();
-  static void ATCommand(const byte *command);
+  static void ATCommand(HardwareSerial * stream,const byte *command);
   
 private:
   static wifiSerialState setup(Stream &setupStream, const FSH *SSSid, const FSH *password,