[SGVLUG] Cable ethernet problems

[Miguel Hernandez]

I was having lots of problems with my Linux network drivers also.
After many reboots (to reset my cable modem) & ifconfig commands it finally
worked.

Do you have another NIC hard laying around to test it, David?
Ideally, it´d be another ISA so you can compare apples to apples.

That´s where I´d start: make sure it´s not your connection or the cables
you´re using.

hope that helps,
--miguel


On Mon, Dec 22, 2008 at 12:22 AM, David Lawyer <dave at lafn.org> wrote:

> I'm having trouble getting ethernet to work using an ISA card from
> 1994 that supports both coax cable (2 types) and twisted-pair.  It's a
> 3com 3c509.  According to the driver doc. it is only half duplex.  I'm
> connecting it to a laptop running Windows XP.  Does it take a
> straight-thru cable or a crossover cable?  I set the Windows driver
> for half-duplex and the Linux driver has been recently changed so that
> it can't be set by options for full or half duplex.  So I would expect
> it to require a straight-thru cable since it should only use one pair
> of wires ??  But the green light on both cards only comes on when I use
> a crossover cable.  Windows says it's connected, but while both
> computers send packets, none are received by the other side and no
> interrupts in Linux are sent.
>
> But I've never used this NIC card (ISA bus)  before and got it with a
> used PC, so it might not work correctly.  The speed is 10Mbps and
> Windows has been told this, so it shouldn't be a speed mismatch.  How
> do I troubleshoot this?  How does half-duplex work over a crossover
> line with 2 circuits.  Does each of the twisted pairs have
> bi-directional flow on them with collisions (half-duplex)?
>
> I suspect that something may be wrong with the linux driver module.
> For one, the instructions are wrong since the change log says the
> option of telling the driver whether it's half duplex, or whether it's coax
> ethernet (which I'm not using) has been removed.  But this option is
> still mentioned in the kernel documentation.  The instruction manual
> for the old ethernet card says that by default it works for coax cable
> and you need to use windows software to change it to twisted pair if
> that's what you're using.  But since the Linux driver used to permit
> you to specify twisted pair, apparently this driver can set up the
> card to use twisted pair.  Perhaps the driver sets it to twisted pair
> in all cases and has disabled the provision of the card to use coax.
>
>
>                        David Lawyer
>
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