Dont look at the adapter, look at the cables. Its been years since I made cables though, so this may be a bit off. But long, long ago ethernet cables could be made certain ways. And in many cases, they had to be made a specific way depending on the application. Then came along tech that allows auto-sensing of the cable being used. For example, long ago if you wanted to connect to computers you had to use a cross-over cable. If you used a straight, it would not work.

Again, with all this new auto-sense stuff I think most cables made are now cross-over style. So if the cable is too "modern" for the adapter, it may not work right. Google ethernet cable types and check the ends. Its why they are made clear after all!