procedure H2A(HexFile, AsciiFile: string);
var
  h, a  : TextFile;
  s1, s2: char;
begin
  AssignFile( a, AsciiFile );
  AssignFile( h, HexFile );
  Reset( h );
  Rewrite( a );
  while NOT eof( h ) do begin
    Read( h, s1, s2 );
    Write( a, Chr( StrToInt( '$' s1 s2 ) ) );
  end;
  CloseFile( h );
  CloseFile( a );
end;    procedure A2H(AsciiFile, HexFile: string);
var
  h, a  : TextFile;
  s     : char;
begin
  AssignFile( a, AsciiFile );
  AssignFile( h, HexFile );
  Reset( a );
  Rewrite( h );
  while NOT eof( a ) do begin
    Read( a, s );
    Write( h, Format( '%.2x', [ Ord( s ) ] ) );
  end;
  CloseFile( h );
  CloseFile( a );
end;

procedure TextToHex;
var
  Txt,Hex:TStrings;
  ps,pd: PChar;
begin
  Txt := TStringList.Create;
  Hex := TStringList.Create;
  try
    Txt.LoadFromFile('E:\Text.TXT');
    ps := PChar(Txt.Text);
    GetMem(pd, 2 * Length(Txt.Text));
    BinToHex(ps,pd,Length(Txt.Text));
    Hex.Text := StrPas(pd);
    Hex.SaveToFile('E:\Hex.TXT');
  finally
    FreeMem(pd);
    Txt.Free;
    Hex.Free;
  end;
end;    procedure HexToText;
var
  Txt,Hex:TStrings;
  ps,pd: PChar;
  L : Integer;
begin
  Txt := TStringList.Create;
  Hex := TStringList.Create;
  try
    Hex.LoadFromFile('E:\Hex.TXT');
    ps := PChar(Hex.Text);
    L := Trunc(Length(Hex.Text) / 2);
    GetMem(pd,L);
    HexToBin(ps,pd,L);
    Txt.Text := StrPas(pd);
    Txt.SaveToFile('E:\Text.TXT');
  finally
    FreeMem(pd);
    Txt.Free;
    Hex.Free;
  end;
end;