You are correct that rings are needed at both ends but it is entirely possible for a ship to deploy rings remotely to the ground and use them as one terminal. The Leonidas was deploying the rings remotely from orbit (which is probably grossly expensive in terms of power consumption, but the Leonidas can one-shot a Hatak, it's not short of power).
D for Drakensis
You're only young once, but immaturity is forever.
D for Drakensis
You're only young once, but immaturity is forever.