public static function decodeFilterASCIIHexDecode($data) {
		// intialize string to return
		$decoded = '';
		// all white-space characters shall be ignored
		$data = preg_replace('/[\s]/', '', $data);
		// check for EOD character: GREATER-THAN SIGN (3Eh)
		$eod = strpos($data, '>');
		if ($eod !== false) {
			// remove EOD and extra data (if any)
			$data = substr($data, 0, $eod);
			$eod = true;
		}
		// get data length
		$data_length = strlen($data);
		if (($data_length % 2) != 0) {
			// odd number of hexadecimal digits
			if ($eod) {
				// EOD shall behave as if a 0 (zero) followed the last digit
				$data = substr($data, 0, -1).'0'.substr($data, -1);
			} else {
				self::Error('decodeFilterASCIIHexDecode: invalid code');
			}
		}
		// check for invalid characters
		if (preg_match('/[^a-fA-F\d]/', $data) > 0) {
			self::Error('decodeFilterASCIIHexDecode: invalid code');
		}
		// get one byte of binary data for each pair of ASCII hexadecimal digits
		$decoded = pack('H*', $data);
		return $decoded;
	}