AS/400 9404 and TWINAX questions...

From: Roger Merchberger <>
Date: Mon Sep 27 00:23:38 2004

Rumor has it that Don Hills may have mentioned these words:
>Wolfgang Eichberger <> wrote:


>You can use CAT 5 with special baluns and filters, but only for short runs.

Most (all?) Cat5 baluns use pins 4 & 5 for this run -- making sure that
pair is part of a twisted pair will help a *lot*.

Good news: You could even make an Ethernet/Twinax single jack, if you're
not running faster than 100Mbps ethernet, as they run 1/2 & 3/6 for their
pairs -- just use 4/5 for twinax.

Bad news: *Most* pre-built cables don't follow the standard as to where the
twisted pairs should be - most just go 1/2 - 3/4 - 5/6 - 7/8 - and that's
bad for both Ethernet & twinax. You'll wanna punch down and/or build your
own cables if you're going to do this.


>Note: Don't just power it off while running after it has IPLed. You'll be in
>for a very long (up to a full day in some cases) rebuild phase on next power
>up. That's why many AS/400 systems had battery backup like yours, so they
>could be shut down properly if there was a power failure. I think I remember
>the command... PWRDWNSYS *IMMEDIATE

Amazingly, that's one of the (if not *the*) most damaging commands to the
system... and it's the *first* one you read about in the IBM manuals...
(well, the ones I read, anyway)!

Anywho, HTH!
Roger "Merch" Merchberger

Roger "Merch" Merchberger   ---   sysadmin, Iceberg Computers
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Received on Mon Sep 27 2004 - 00:23:38 BST

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