Configuring Combo Coax/Twisted-Pair
Last updated: 2/2/02
Q. How does one make a combo coax/twisted-pair
network adapter that works in a thinwire coax network work in a twisted-pair
A. Combo network adapters or Network Interface
Cards (NICs) are designed to work with either 10BASE2 "thinwire" coax
(http://duxcw.com/faq/network/10base25.htm) Ethernets or 10BASE-TX twisted-pair
Ethernets. They have coax connectors and RJ-45 jacks on the back of
the card. Most of these boards have one or more of four ways for configuring
them to use one media interface or the other:
- Some detect the media automatically.
- Some have flash memory and the interface can be changed
with a utility/diagnostic program that came with the NIC.
- Others have a jumper(s) to change the media interface.
- As I recall(?), some some of them can be changed in
You may be able to determine the manufacturer, etc. (http://duxcw.com/
faq/network/mac.htm and http://duxcw.com/digest/Fromshop/mb/det.htm) of the
NIC and download the manual and software.
Another problem you ought to be aware of has to do with
Windows and non-PnP (or those set to use a specific IRQ instead of Plug 'n
Prey), Novell-compatible NE2000 NICs. Many old combo NICs are NE2000-compatible. The
problem is that Windows 9X often insists on assigning IRQ 3 (http://duxcw.com/faq/irq/irq.htm)
to a Novell-compatible adapter when the adapter is actually set for another
IRQ. The fix is to determine what the real IRQ is and change it in Control
Panel, System, Device Manager. I usually (or used to) set non-PnP/ISA
bus NICs to IRQ11, but that doesn't always work.
My advice... When you upgrade from coax to twisted-pair,
replace the NICs. Good ones cost noticeably less than $20 each.