10/100 EtherJet CardBus Adapter problem

I have a IBM thinkpad and I wanted to connect it to my LAN, I installed the card, it is also an ibm and a 32-bit pc card. Anyway I wanted to use the ethernet/networking port in the back of my thinkpad and the helpcenter said If it was sealed, with a little plastic block, than I needed to use the card. The problem is that I dont have a LAN Adapter Cable, Which then the Rj45 cord goes into. I just wanted to connect the rj45 cord to the network port on the back of my computer not through the card, if this is impossable or possable help would be great. Thanks anyway and the operating system is windows NT 2000 professional