Long Cable, Slow Network
Last updated: 7/22/04
Q. Why would 100BASE-TX network adapters only operate
at 10 MHz when two computers are connected with a long cable?
A. This can be caused by a defective cable,
the wrong kind of cable, a cable that is improperly installed, the wrong
kind of RJ-45 plugs, cables that are not wired properly, a bad crimp, or
defective network adapters. It can also happen with poorly made or
improper cables of any length.
The cable should be solid core and rated CAT 5 or higher
(jacks and short lengths of stranded cable can be used at either of both
ends of the cable--see reference at the bottom of this page).
The cable should be installed following the rules at http://duxcw.com/digest/Howto/network/cable/cable9.htm.
The RJ-45 plugs should be rated CAT-5 or higher and designed
for solid core wire (there are RJ-45 plugs for stranded wire).
The cables should be wired according to http://duxcw.com/digest/Howto/network/cable/cable6.htm.
The important thing is that the Ethernet transmitters be connected to the
Receivers with wires for the SAME twisted pair. If they are not you may see
the symptoms you describe, especially with longer cables.
Bad crimp: see All About Crimping at http://duxcw.com/digest/Howto/network/cable/cable8.htm.
Run diagnostics and C:\>net /diag on the adapters.