Re: (PM) what are the optimum line levels for CT1?

Jay Hennigan (jay@west.net)
Fri, 3 Jul 1998 07:49:26 -0700 (PDT)

On Fri, 3 Jul 1998, jay wrote:

> Would anyone know the best line levels for receiving a channelized T1? We
> have less than 200 feet of copper between us and the 5E,
> and the two lines were arriving at -5.5 and -5.0. The first T made the
> pm3 report -7.5 to -15 db, the second +2 to -7.5.
>
> Apparently the pm3 is mis-calibrated by 2 db? I wish they had programmed
> the box to report the actual db instead of just a range.

It may be slightly off, but the actual level really isn't that important.
What you're asking for is an accurate logarithmic AC voltmeter going down
to the millivolt range for signals above 1 MHz. A rather complex, and
sensitive piece of analog test equipment for a digital box. I'd rather
they come up with a way to make v.90 work without breaking things. ;-)
The actual signal level isn't nearly as meaningful as the error rate.
At least one thread on the list earlier indicated problems when the
levels were slightly too high.

> Anyway, they set the westel cards to 're-juvenate' or something, making
> their T-bird test equipment report -1, but we are still having trouble.
> show line x doesnt not report any errors.

If you aren't showing any errors, then there isn't likely anything wrong
with the incoming lines.

> Currently running b17, have tried b15, same thing. Symptoms are trouble
> negotiating, disconnects, slowing traffic flow if the connection holds.

This is a well-known problem with revisions above b13. Flash back to b13,
forget v.90 for now, and call support to make sure they know it's really,
really still broken.

-- Jay Hennigan jay@west.net 805-884-6323 --
WestNet: Internet service to Santa Barbara, Ventura and the world.

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