So datalink is not everywhere in DCS. There are some server where even the f16 have to do the iff checks. And the most Server have not the same jets for each side. So even IRL it’s unrealistic that an su27 appears in the RWR behind you in a blue zone and you have to check if it’s friendly or not. Know your enemy’s and friendly RWR signals. On the DDCS server even the f15 pilots have no issues to know if it’s friendly or not. Communication, AWACS, RWR is your key. Not datalink.