Old 30 Pin cables - differences?

[AL1630]

I know this question is about 10 years out of date, but I just pulled out my old iPod, iPhone 3GS, and some random cables. I was noticing that I have a couple 30 pin cables with different ends. Both have USB on one end and 30-pin on the other, but the 30 pin sizes are different. One has a smaller plug like the one on Apple's website that I think is newer, and there's another with a larger plug and release buttons on the side. There's another with firewire but that's obviously different. Is there any real difference between the two USB ones or did the design just change for some reason?

Here's what each looks like:

 

[Juicy Box]

Is there any real difference between the two USB ones or did the design just change for some reason?

AFAIK, the only differences is that the larger dock cable has little release buttons on the sides. It locks into the device, the the buttons release the connector from the device.

 

[AL1630]

Thanks! Wonder why they changed it. Less moving parts is better, I guess.