What's the difference between 2 nikon shutter release cables?

I'm going to buy one for my Nikon D3100 so it has to be compatible. What is the difference between the Nikon mc-dc1 and mc-dc2 remote release cord?

The MC-DC1 is only for the Nikon D70s and D80 cameras. You need the MC-DC2 for your D3100.
http://www.nikonusa.com/...s-Overview

The DC2 is the only one listed for your camera

http://www.nikonusa.com/...ccessories

The cables have different connectors, so each one is specific to certain cameras.