From Linksys, A Division of Cisco Systems:
The EtherFast 10/100 LAN Card has undergone a few revisions and improvements over the years. There are currently four versions of the card. The version of the card you have depends on when you bought it. Since each card uses a different set of software, make sure you download the right drivers for your version of the card. To tell the cards apart, look at the CPU chip on your card. (It's normally the largest chip you can see). Some cards' chip will have LINKSYS printed on it, some have PNIC printed on it, while others will read DIGITAL. A description and picture of each chip & card version is shown below, along with a link to the download file(s) you'll need. The Manual for the LNE100TX card with Wake-On-Lan support is available for download (size 2.2MB). Note that each card's regular drivers are stored across two disks, and you'll need to download both. Each disk is between 200 and 600KB in size.