The Cord (電気コード denki-kōdo ) is an event item in Resident Evil 2.
"A cord to connect wires on small electric devices."
"小電力用のケーブルコードだ コードが切れているところに使えるはずだ "
It is used to connect the shutter mechanism to the shutters in either the corridor to the west of the western waiting room, or on the corridor leading to the basement, blocking the windows.
In the A game, by the time the zombies break into those hallways, they'll only enter the corridor the Cord wasn't used in. In the B game, the mechanism holding the shutters short-circuits and opens, allowing the zombies to pass.
For some reason, the hallway the Cord wasn't used in won't have any zombies in the B game – they won't even appear in the break-in cutscene (they will if the cord wasn't used at all, though). This allows the player to decide which path will be easier in which game.
It can be found in the Raccoon City Police Station's Witness Interrogation Room in the A game.