Welcome to APUG!
I an guessing a bit here.
My guess is that you have a synch cord for your Canon flash that has a proprietary Canon plug on one end, and a male pc synch terminal on the other end.
Your Copal 0 shutter also has a male pc synch terminal on it.
So you need a cord with two female pc terminals - one at each end.
Paramount cords is certainly one resource that can supply this.