uses
  ShellAPI;

procedure TForm1.Button1Click(Sender: TObject);
begin
  case OSVer of
    VER_PLATFORM_WIN32_NT:
        {connection_name = the name of the connection in "Network and
        DialUp Connections", logon = logon string, password = password string.
        All are separated by spaces.}
        ShellExecute(Handle, 'open', 'rasdial.exe', 'connection_name logon password', nil, SW_HIDE);
    VER_PLATFORM_WIN32_WINDOWS:
       (*
      Dial Up Networking (DUN)
        module:
                RNAUI.DLL
      command:
                rundll32.exe rnaui.dll,RnaDial {name of connection to establish}
          result:
                displays the Connect To dialog for the passed connection
      *)
      ShellExecute(Handle, PChar('open'), PChar('rundll32.exe'),
        PChar('rnaui.dll,RnaDial exact name of dialer entry TRACERT -h 1 -w 1'),nil, SW_NORMAL);
  end;
end;

