code: private static char[] mapChar (byte[] digits) {
  		char[] result = new char[digits.length];
  
  		for (int i=0; i<digits.length; i++)
  			result[i] = mapChar(digits[i]);
  
  		return result;
  	}
docs: Maps ADS-B encoded to readable characters
  @param digits array of encoded digits
  @return array of decoded characters