diff --git a/DateTimeCore.cpp b/DateTimeCore.cpp
index 9eb5a5a..29932f6 100644
--- a/DateTimeCore.cpp
+++ b/DateTimeCore.cpp
@@ -125,7 +125,7 @@ char const *  GetDateStr( const char * DateSeparator )
 
     // Build String
     sprintf( ReturnStr, "%04d%s%02d%s%02d",
-                        Year, ((DateSeparator)? DateSeparator : "/"), Month, ((DateSeparator)? DateSeparator : "/"), Day );
+                        Year, ((DateSeparator)? DateSeparator : ""), Month, ((DateSeparator)? DateSeparator : ""), Day );
 
     // Return value
     return (ReturnStr);
@@ -143,7 +143,7 @@ char const *  GetTimeStr( const char * TimeSeparator )
 
     // Build String
     sprintf( ReturnStr, "%02d%s%02d%s%02d",
-                        Hours, ((TimeSeparator)? TimeSeparator : ":"), Minutes, ((TimeSeparator)? TimeSeparator : ":"), Seconds );
+                        Hours, ((TimeSeparator)? TimeSeparator : ""), Minutes, ((TimeSeparator)? TimeSeparator : ""), Seconds );
 
     return (ReturnStr);
 }
@@ -164,8 +164,8 @@ char const *  GetDateTimeStr( const char * DateSeparator, const char * TimeSepar
 
     // Build String
     sprintf( ReturnStr, "%04d%s%02d%s%02d %02d%s%02d%s%02d",
-                        Year, ((DateSeparator)? DateSeparator : "/"), Month, ((DateSeparator)? DateSeparator : "/"), Day,
-                        Hours, ((TimeSeparator)? TimeSeparator : ":"), Minutes, ((TimeSeparator)? TimeSeparator : ":"), Seconds );
+                        Year, ((DateSeparator)? DateSeparator : ""), Month, ((DateSeparator)? DateSeparator : ""), Day,
+                        Hours, ((TimeSeparator)? TimeSeparator : ""), Minutes, ((TimeSeparator)? TimeSeparator : ""), Seconds );
 
     return (ReturnStr);
 }
diff --git a/DateTimeCore.h b/DateTimeCore.h
index 713ae86..6d0b99c 100644
--- a/DateTimeCore.h
+++ b/DateTimeCore.h
@@ -23,9 +23,9 @@ bool    GetTime( unsigned char &Hours, unsigned char &Minutes, unsigned char &Se
 bool    SetDate( unsigned char Day, unsigned char Month, unsigned Year );
 bool    GetDate( unsigned char &Day, unsigned char &Month, unsigned &Year );
 
-char const *  GetDateStr( const char * DateSeparator = NULL );
-char const *  GetTimeStr( const char * TimeSeparator = NULL );
-char const *  GetDateTimeStr( const char * DateSeparator = NULL, const char * TimeSeparator = NULL );
+char const *  GetDateStr( const char * DateSeparator = "/" );
+char const *  GetTimeStr( const char * TimeSeparator = ":" );
+char const *  GetDateTimeStr( const char * DateSeparator = "/", const char * TimeSeparator = ":" );
 
 //---------------------------------------------------------------------------
 
diff --git a/JSONparseCore.cpp b/JSONparseCore.cpp
index 374bdee..358b8b4 100644
--- a/JSONparseCore.cpp
+++ b/JSONparseCore.cpp
@@ -769,7 +769,7 @@ bool CJSONparse::PrintString( char * String, int Len )
                 case '\\':  write( OutputHandle, "\\\\", 2 );   break;
                 case '"':   write( OutputHandle, "\\\"", 2 );   break;
                 default:
-                    dprintf( OutputHandle, "\\u%04d", *BufPos );
+                    dprintf( OutputHandle, "\\u%04X", (unsigned char)*BufPos );
                     break;
             }
             BufPos++;