Even if the electrical inspector passes the unterminated cable, don't your guys give you grief for having an open ring?? Our local inspectors HATE low voltage rings, especially on exterior walls, and they make us plate and terminate everything to keep fire and/or moisture from moving into or out of the walls. I know in WI and MN they have use special foam gasketed J-boxes or these plastic back boxes and a specific grade of vapor barrier tape to seal behind open rings... It's not in the IL code yet, but sometimes they mention it to us if we're there, but haven't flagged anything yet.