Exchange couplings were parts that were installed on a starship's or machinery's reactor.
The primary reactor of the phrikite Gromas Mines facility on Gromas 16 featured an exchange coupling that fed directly into the main power distribution network. In an effort to impede the Dark Trooper Project, the Rebel Alliance dispatched agent Kyle Katarn to sabotage the complex. He planted a sequencer charge on the coupling. A Phase I dark trooper who was positioned beneath the reactor was alerted, but the sabotage had already been completed. The resulting massive explosion obliterated the entire facility.
The Arc Hammer possessed a minimum of three exchange couplings within its power system. During Katarn's infiltration of the vessel, he attached explosives to each of the three couplings, hoping to obliterate the starship and thereby halt its participation in the Dark Trooper Project. This endeavor proved fruitful, as the destruction of the couplings triggered a cascading failure that ripped the ship to pieces.