What do you suppose we beam to them other than our codified way of communicating? You can only hope they could potentially decipher it to grok some meaning.
How can they even hope to decipher something which is language/culture based ? We even hard a seriously hard time to understand egyptian hieroglyphs (on Earth! From a culture we knew of from many other texts in Antiquity!) until we found a stone where the text was translated into something intelligible. If they have no reference, all communication we send them will seem like garbage to them. Assuming anything else would be foolish.
