/**
  * Constructor
  */
 function BCGcode39extended()
 {
     // public
     BCGcode39::BCGcode39();
     // We just put parenthesis around special characters.
     $this->keys[$this->EXTENDED_1] = '($)';
     $this->keys[$this->EXTENDED_2] = '(/)';
     $this->keys[$this->EXTENDED_3] = '(+)';
     $this->keys[$this->EXTENDED_4] = '(%)';
     $this->errorText = '';
 }