"Please call me Tanaka."
There isn't really any, except the context of the situation. The only difference in the actual grammar is that if I were asking you to call Mr. Tanaka, I'd probably say "Tanaka-san." But if I'm asking you to call ME Mr. Tanaka, I would never add "san" to myself. "san", "sensei" or any other title are only used for other people. So there is a little clue there. But the real issue is that there are lots of Japanese sentences that are ambiguous without knowing the context. But the situation that you are in when you hear the sentence should clear up the ambiguity.