[c-nsp] Line Code Violations on DS3

[Joseph Jackson]

On 2/1/08, Gregory Boehnlein <damin at nacs.net> wrote:
>
> > >> Try putting a 12 db attenuator on the transmit portion, then re-try
> > your
> > >> loopback. We've found that the PA-MC-T3 cards tend to overdrive the
> > DS3 a
> > >> bit, and the only way that we've been able to get rid of the errors
> > is
> > >> attenuating the transmit load.
> > >
> > > Interesting, you're saying to put an attenuator on the transmit
> > portion of
> > > the card. Some of the Cisco documentation is saying to put it on the
> > receive
> > > portion. Is there any way using the "show controller" output to tell
> > which
> > > one has the "hot" signal?
> >
> > He meant on the PA's receive (the telco's transmit).  PA-MC-T3s are
> > somewhat notorious for being sensitive to overly hot signals...where
> > cisco's definition of 'overly hot' is 'normal' to several other
> > vendors.
> >
> > In a pinch, if you can't find a suitable attenuator, you can use a
> > really long service loop and/or multiple DS3 cables connected together
> > using barrel connectors.  We have at least one installation where after
> > switching from a CAC Widebank28 to an Adtran mux, we ended up needing a
> > coiled up 50' "service loop" sitting on top of the mux to keep the
> > PA-MC-T3 happy.
>
> Jon, yes.. thank you .. that was exactly what I was getting at..
>
> We, too, have several DS3's w/ 75 feet of coiled up cable sitting in the
> bottom of a cabinet to get the Adtran MX-2800s and the PA-MC-CT3's to play
> nice together. I know that to most people that sounds counter intuitive,
> but
> keep in mind the signals were meant to be driven over much longer
> distances
> than the typical 6 foot Patch Panel to CPE that exists in lots of data
> center installations.


Ok this might sound weird but I LOVE YOU GUYS.  We've been having this
problem using an adtran mux.  Line code violations and P-bit errors all over
the place on only one end.  I was just about to email the list when I
thought I'd better search for this problem.  I'm going to try the stuff
suggested now.


Thanks!

Joseph