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Re: Ethernet collision with modem?



Eli Marmor wrote:

>> >I have installed Ethernet Gold2000 card (NE2000 compatible) into my PC
>> >and my modem stopped working ... After removing it it came to work again.
>> >The modem was online but it couldn't dial...
>> >How can it make a collision? my modem is using /dev/cua1 (external) but I
>> >didn't configured the /dev/ethX yet. Is it possible? There no jumpers on
>> >the card ???
>>
>> Sounds like an IRQ conflict. Check whether the Eth adapter uses
>> (or defaults) to IRQ3.
>>
>> Doron Shikmoni
>
>BTW: Is it possible to use more than 2 COMs concurrently?  I spent
>3 hours on that, today. COM1 is used by the mouse, and COM2 by the
>modem. I want to be the "console" of a router, so I configured the
>unused port to be COM4, but it seems to have collision with IRQs.
>One of about 10-20 characters is got, and the others lost. I did the
>checks with minicom, but there must be something simpler for direct
>communication, is there?
>(I didn't forget to disable the agetty of the tty).

A little-known rule in PC architecture is that COM port must be
in consecutive order, with no "holes". I.e., it's "illegal" to
have COM1, COM2 and COM4 (without COM3).

Many of you may jump right at me with "well I do that all the time
and it works". I know. That may be the case with some software;
then again, other software may fail and the overall status is -
as they say - "unpredictable". Some things work, some things break.

So, to start with - make all your ports in consecutive order.
I make it a habit to always make a serial mouse COM2.

The next issue to face is IRQs. Traditionally, COM1 and COM3
use the same IRQ (4), while COM2 and COM4 share another (3).
This means that with most software, using COM1 halts COM3 and
vice versa.

If you need 1&3 or 2&4 to work concurrently, the way out is to
define a non-traditional IRQ to one of them. Say, define COM3
to have IRQ5. You will then have to tell your software about
it. Easily doable in Linux, doable in Win95, per-program option
when in DOS (say, Kermit).

That's the COM story in a nutshell.

>P.S.  Stas!  If anybody wants you to charge the *real* cost, you
>should agree... by doubling the price!
>I ordered 2 weeks ago the freeware OS, NetBSD, by FedEx, from
>Infomagic. This "free" CD cost $35, +$37 for shipping, +81 NIS for
>Flying Cargo (like in Sdom-VaAmora: this CD "layed" 80 hours in their
>store in Lod, because Kfar-Saba was too far for them from Lod. The
>way from Arizona to Lod took only 36 hours!  So I had to pay for their
>laziness!). Total cost was 340 NIS. Stas, don't be shamed, take more!
>We are all (or at least me) in the back of you!

Next time try this: Comtact cdromsonline.com (by way of telnet, or WWW).
Search for "infomagic" and/or "worldprice". You will find the Infomagic
6-CDROM package (issued quarterly), with Slack, RH, and Debian plus
full sources and sunsite (and other) archives, for about $25. This
includes the 6 CDs plus shipment to anywhere in the world (!!). The
only "drawback" (if you can call it that) is that it's not FedEx or DHL,
but rathet airmail. This means about 10 days delivery. But the price,
the price...

Doron Shikmoni