Re: DS3 Coax..

[Josh Richards <jrichard () cubicle net>]

Makes sense but...

Before fiber and ADMs were so common, in the days of buried coax for
DS-3s (between COs and for the occassional large customer), coax was
obviously being used for inter-building connectivity.

How exactly did the topology differ?  Besides fiber, which eliminates
the issue of ground loops and such altogether, how did the RBOCs actually deal
with this problem when they didn't have fiber in the ground?

I presume there's an element/architecture that can be used safely.  Mike alluded to
a 'GID' per Sprint.  Anyone have a reference/source for this device?

-jr

* Timothy R. McKee <tim () baseworx net> [20030419 18:13]:
> Definately.
>
> You most emphatically do NOT want copper going across your parking lot.
> Besides the danger from lightning strikes and other electrostatic discharges
> you run the risk of ground potentials differing significantly.  You could
> wind up with a significant amount of current flowing across the coax just to
> balance building grounds.  (This is why telcos insist on a single ground
> point and have that point connected to an array of ground rods driven deep
> in the ground.)
>
> Tim
>
> -----Original Message-----
> From: owner-nanog () merit edu [mailto:owner-nanog () merit edu]On Behalf Of
> Robert E. Seastrom
> Sent: Thursday, April 17, 2003 11:51
> To: Mike (meuon) Harrison
> Cc: nanog () merit edu
> Subject: Re: DS3 Coax..
>
>
>
>
> "Mike (meuon) Harrison" <meuon () highertech net> writes:
>
> > I need to run a DS3 across our parking lot.. Seriously.
> >
> > What's the max length I can use coax for (I know, gotta use a GID),
> > and what's the best brand/type of coax I can use? It'll be through
> > innerduct.. Looking for some real world answers from people that do
> > a LOT more of this than me..  (It might take 350-400 feet).
>
> The textbook limit is 450' for 735 cable.  I've had poor luck pushing
> the limit, and don't know offhand if using some other flavor of 75 ohm
> cable buys you anything.
>
> Were I in your position, I'd have glass pulled and use a coax to fiber
> media converter such as http://www6.adc.com/ecom/hier?NODE=OND68947,
> http://www.versitron.com/DS3T3.html, or
> http://www.rad-direct.com/DATASHEET/FOM-T3.pdf (the latter of which
> I've used personally) on each end.  No, it's not the cheap way to do
> it, but it eliminates ground loops and other such nastiness that can
> ruin your whole day.
>
>                                         ---Rob

-- 
----
Josh Richards <jrichard@{ geekresearch.com, cubicle.net, digitalwest.net }>
Digital West Networks, Inc - San Luis Obispo, CA 
KG6CYK - IP/Unix/telecom/knowledge/coffee/security/crypto/business/geek