[geeks] Whee! Lightning strikes, AGAIN!

[gsm at mendelson.com]

On Tue, Jul 28, 2009 at 12:25:14AM -0400, Lionel Peterson wrote:

>I'm not following you - are you saying that in Cat5e/Cat6 there are
>four pairs communicating, or are you discussing Fiber?

Yes. 10Base-T and 100Base-T use 2 pairs, each at the rated speed, if you
look at a plug with the tab up, wires 12345678, 1 and 2, 3 and 6. Up until 
recently (2001 or so in high end stuff, 2005 or so in cheap stuff) direction
mattered. Wires 4 and 5 were reserved for telephones so that if you accidently
plugged a telephone line into an ethernet, it did not explode when the phone
rang.

1000Base-T is 4 separate pairs, each running at 250mbps. Each pair is used
bi-directionaly, i.e. data flows both ways.


Fiber runs at its rated speed. Are there still two fibers (one in 
each direction?) 



>I'm nearly at the point where I want RJ45 patch panels with surge
>supressors on each jack, that or a big knife switch on any long runs.


For 1000base-T you would need 8 for each connection, and they would have to
be rated at least 500mHz, if not faster. At what I expect would be the 
price, separate 802.11N connections (each one on its own channel) would 
be cheaper. 



>I appear to have several (up to 8?) computers that got their NICs
>fried, and the A/C that got mangled needs a new controller board and a
>new motor (when the relay on the controller failed, it stopped the fan
>motor. Without the fan motor running, the pipes iced up, then when I
>tirned it off, the ice melted, dripping into the motor and killing
>it...
>
>This one of my least fun days in recent memory. Everything I touch
>seems to be broken - I can't catch a break.
>
>Happily, I got my new cable modem installed, swapped in a WRT-DD
>router for one with (apparently) fried ports, then I swapped a Cisco
>2950 in for a now *zapped* Netgear 10/100 24 port switch... Basic
>connectivity is up, and now I have to test machines and diagnose NIC
>failures in each box.
>
>Argh.
>
>(I'm currently trying to get an old Intel Pro/100+ NIC to work in my
>daughter's machine, but it insists on netbooting, and I can't figure
>out how to stop it (nothing in the NIC setup program to do that, and
>the BIOS doesn't list network boot, so I can't disable it there)...
>Rather than "waste" a gigabit NIC on this old Dell DImension 4700, I
>may use the occasion to upgrade her box to something with a faster CPU
>and a built-in NIC. This thing is a bit s-l-o-w by current standards.)

Look and see if you can disable the ROM using either the setup program
or the utility.

Make sure you download the full package (pro2kxp.exe) and install everything.

Look for a "use alternate boot devices" option in the ROM.


Geoff.

-- 
Geoffrey S. Mendelson, Jerusalem, Israel gsm at mendelson.com  N3OWJ/4X1GM