Mac Mini cable question

I want to connect my mid-2011 Mac Mini to an external drive of about the same age for backups. I need to get a cable to connect them. The only ports they have in common are USB 2.0 and FireWire 800. FireWire would be better/faster, right?

I'm looking on Amazon at FireWire cables and I have to specify how many pins each end has, but how do I tell? I tried looking at each port with a flashlight, but I can't see the pins. I looked at the page on the Apple web site describing my model's ports and connectors, but it doesn't say. I'm not finding the port info for the drive on the OWC web site either. Help!

i have have always just connected via usb. Even when I was duplicating most of the drive, it did not take that long to do. 

are you local? I have a drawer of cables. Also, while they have pins, I've only ever paid attention to the 400 or 800 part for FireWire. Tell me which one you'd like and I'll look and see what I have. 

Thanks, joy, but I'm not local. I found a store nearby that sells FireWire cables and I'm back in business.