Need help identifying iBook cables

My question should be easy to answer, but it's about a 2002 A1005 G3/600 iBook . . .so maybe it's not that easy.

I bought it on a whim . . . brand new . . . in late summer 2002 . . . loaded it with all the contemporary software I was relying on at the time — but only used it a couple of times before sticking it on a shelf inside the "fancy shmancy" Targus tote bag I had purchased for it and forgetting about it.

Three or four years later I remembered it, when my back-up desktop Power OC G4 looked like it was failing; so I pulled the iBook out of hiding and saved all the files that looked important and returned the iBook to the shelf . . . A couple of years later, when the CD tray on my primary desktop Mac G3 failed, I did the same thing. Saved files and set my iBook aside.

I rediscovered it a couple of week ago . . . hidden under a pile of papers in my "home office" . . .and promptly kicked myself for having wasted all that $$$ on a device I hadn't needed in the first place. (So what if the iPad I bought last year has already met the same fate?)

While I'm not ready to give up on that one yet, I am thinking about selling the iBook and all its software and accessories, which still are in near-new condition. I've sorted thru and trashed the files that weren't worth saving in the first place . . . saved the rest to an external hard drive . . . and emptied the trash can filled with all the original documents.

But in the midst of examining the Targus bag, I just discovered 3 cables stored I had never seen before buried inside one of the large pockets— all still wrapped and/or sealed in their original condition. I've figured out what two of them are, but am stuck on the third. I haven't uncoiled it, but it looks like it's probably 30-36 inches in length . . . very skinny . . . and has what look like either an ethernet or telephone jack (with 4 very shiny visible gold pins) on each end.Since the other two items are adapters that must have been included with the iBook in the same box, I'm guessing this item must be similar. I just can't figure out what it would have been used for.

Suggestions, anyone?