diff --git a/LiteProtocolCore.cpp b/LiteProtocolCore.cpp
index e4d2755..92ebdd8 100644
--- a/LiteProtocolCore.cpp
+++ b/LiteProtocolCore.cpp
@@ -196,6 +196,7 @@ bool CLiteProtocol::NewCommandStr()
         free( CommandStr );
         CommandStr  = NULL;
         BufferSize  = 0;
+        Length      = 0;
     };
     IncCommandStr( 14 );
 
@@ -346,21 +347,31 @@ bool CLiteProtocol::AppendParam( const char * pString, const int pLength )
     int     StringLen;
 
     // Check if valid
-    if (!pString)
-        return false;
+    if (!pLength || (!pString && (pLength == -1)))
+    {
+        // Increase string length if required
+        StringLen = 0;
+        IncCommandStr( Length + 1 );
 
-    // Increase string length if required
-    StringLen = (pLength < 0)? strlen(pString) : pLength;
-    IncCommandStr( Length + StringLen+1 );
+        // Copy string
+        CommandStr[CurrPos+StringLen] = Separator;
+        Length += 1;                              // Allow for separator character
+    }
+    else
+    {
+        // Increase string length if required
+        StringLen = (pLength < 0)? strlen(pString) : pLength;
+        IncCommandStr( Length + StringLen+1 );
 
-    // Copy string
-    memcpy( &CommandStr[CurrPos], (char*)pString, StringLen );
-    CommandStr[CurrPos+StringLen] = Separator;
-    Length = Length + StringLen + 1;          // Allow for separator character
+        // Copy string
+        memcpy( &CommandStr[CurrPos], (char*)pString, StringLen );
+        CommandStr[CurrPos+StringLen] = Separator;
+        Length = Length + StringLen + 1;          // Allow for separator character
+    }
 
     // Move pointer to end and set end char
     CurrParam++;
-    CurrPos = CurrPos + StringLen + 1;        // Allow for separator character
+    CurrPos += StringLen + 1;                     // Allow for separator character
     CommandStr[CurrPos] = EndChar;
 
     // Update references
diff --git a/LiteProtocolCore.h b/LiteProtocolCore.h
index 50871fd..94451b4 100644
--- a/LiteProtocolCore.h
+++ b/LiteProtocolCore.h
@@ -88,8 +88,12 @@ class CLiteProtocol
                              int * FromLen = NULL, int * ToLen = NULL, int * CommandLen = NULL );  // Read core parameters from structured command: To, From & Command
 
         // Read structured Command string
-        inline int             GetNoOfDataParams()           { return (NoOfParams - 3); };                      // Return number for data (additional) params
-        inline bool            GotoDataParam( int ParamNo )  { return (GotoParam( ParamNo+3 )); };              // Goto specific data (additional) param
+        inline int             GetNoOfDataParams() {                                                            // Return number for data (additional) params
+            return (NoOfParams - 3);
+        };
+        inline bool            GotoDataParam( int ParamNo ) {                                                   // Goto specific data (additional) param
+            return (GotoParam( ParamNo+3 ));
+        };
         inline char const *    GetDataParamNo( int ParamNo, char ** pString = NULL, int * pLength = NULL )  {   // Read specific data param (by number)
             return (GetParamNo( ParamNo+3, pString, pLength ));
         };