If the equipment doesn't have shielded jacks, then the correct answer, in my mind, is to ask the engineer who specified it this way just what, exactly, he wants.
I suspect the problem with that approach, though, is that he doesn't have a clue. (Otherwise, he already would have written very careful specs for what he wants.) I'm thinking this is a case of the guy thinking, "Shielded is better than unshielded, so I'll specify shielded."
