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.

AND

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.