Sounds like it's thin ethernet. Nothing wrong with that, although it's now dated and unlikely to fit a modern network card.
The very least you need is a crossover cable, but in the meantime click here
Once you have the gist of what is necessary, if you have any specific questions, please come back and ask.
Incidentally, a search in the helproom for network, will bring up many threads on almost all the problems you may experience.