diff --git a/src/DidacticNet.h b/src/DidacticNet.h
index cad4bd1df8d4a407d50c53f24c8b8e678df576d4..498e953e4186f43160d0752fe72f74d8c6891177 100644
--- a/src/DidacticNet.h
+++ b/src/DidacticNet.h
@@ -8,10 +8,12 @@
 #define _DIDACTICNET_
 
 #include "Arduino.h"
-//callback(topic, topicLength, data, dataLength)
+
 #ifdef CALLBACK_W_LENGTH	 
+	//callback(topic, topicLength, payload, payloadLength)
 	#define PSNET_CALLBACK_SIGNATURE void (*callback)(char*, int, char*, int)
 #else
+	//callback(topic, payload)
 	#define PSNET_CALLBACK_SIGNATURE void (*callback)(char*, char*)
 #endif