Network hardware/cabling problem

I have just installed a new router for my network. The old setup had a simple hub and the computers communicated fine, although I never measured the transmision speeds.

When I installed the new router, the farthest computer indicated that the network cable was unplugged. It wasn’t, and there was nothing wrong with the cable. I tried changing the NIC from the default setting to 100 Mbps. No change. Forced to 10 Mbps, it worked.

The same computer, moved closer to the router and hooked up with a short cable, worked fine on the default setting.

The other computers on this network are communicating at 100 Mbps (although on the next farthest machine it had to be be forced to 100 Mbps; the default setting gave the same cable unplugged message).

The cable run to this machine is only about 115 feet (35m), well under the 100m limit for Ethernet, and the cable is Cat 5. The computer is a Dell Pentium 4 running Windows 2000. The NIC is an integrated 3Com 3C920. The router is a Netgear 802.11g wireless. I can’t see why it shouldn’t be getting 100 Mbps.

Would a new network card possibly overcome this problem? Other suggestions?

Thanks.

Is the cable store-bought or homemade?

It’s raw cable that I put my own connectors on. I just redid the connectors today, to remove excess cable at each end, in the hope that that would help the problem. It didn’t.

If your guess is that the cables or connectors are wonky, I’m pretty sure that’s not it. But if you want to make the case, tell me what you’re thinking and how I could test it.

When you put the connectors on, did you follow the standard or just put them in by pairs? The “A” standard, as I recall, is:

White/blue
Blue
White/Green
Orange
White/Orange
Green
White/Brown
Brown

If you don’t separate wire 3 and wire 6, I’m told, it could drastically effect communications at the higher frequencies.

Sounds like a miswired cable. i’ve done that myself. Compare both ends of the cable and make sure that the connectors are wired identically and that the wires are connected to the proper pins on the connectors. Ethernet depends on signals being sent over twisted pairs of wires. If the connectors are miswired, you no longer have a twisted pair for the signal, just two independent wires that will not work properly at high rates or long distances.

Really? I didn’t know that. They are just paired

White/blue
Blue
White/Green
Green
White/Orange
Orange
White/Brown
Brown

I can easily re-make the connectors and see if that helps.

Thanks for the idea.

Incidentally, the “A” standard I described is formally known as the T568A standard. The T568B is slightly different. The key in either case is that 3 and 6 be the same colour and, of course, that the plugs on each end match.

Bryan: You were right! That fixed it. Thanks a lot!

I suppose I should have checked the order of the colors elsewhere on the Web, but I knew I could rely on the SDMB. What a great place!

Thanks again.

This website describes it in detail. I had the colours wrong, but the premise right.