protected function getBaseData()
{
$data = array();
$data['VERSION'] = static::API_VERSION;
$data['USER'] = $this->getUsername();
$data['PWD'] = $this->getPassword();
$data['SIGNATURE'] = $this->getSignature();
$data['SUBJECT'] = $this->getSubject();
$bnCode = $this->getButtonSource();
if (!empty($bnCode)) {
$data['BUTTONSOURCE'] = $bnCode;
}
return $data;
}