[c-nsp] PA-T3 vs. PA-T3+

[Gert Doering]

Hi,

On Sun, Sep 19, 2004 at 11:43:50AM +0200, Lukas Krattiger wrote:
> We had several issues with T3-Lines and the PA-T3 on both sides, problem was
> packet loss, crc, overruns etc.
> 
> Our workaround sounds maybe a little special, but works perfect:
>  - Increase the resistance between your T3-Card and the Carrier Port (50m
> cable is enough)

In my case, the cable is very short indeed (some 3m or so).  So it might
be a case of "signal too hot", instead of "signal too weak" (which was
my first assumption).

>  - Set you clock source on both side to LINE (T3 specification says you have
> to provide the timing, we just don't do it)

Funny you mention this.  The *other* T3 on the mentioned PA-2T3 is now
running in exactly this configuration (both sides clocking from LINE), 
and is much more stable than the "correct" configuration.

> After this changes our T3-Lines with the PA-T3 are working without errors
> since more then half a year.

Thanks for your data.  Have you talked to your Carrier about this?  Maybe
they can reduce the output signal of their T3 port?  (I certainly plan
to do this, instead of putting addition 50m of cabling into this 
already-crowded edge router rack...)

> We dont't have the issues if we use a PA-T3+ or ADC Kentrox IDSU on one
> side.

Ditto :-)

gert

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Gert Doering - Munich, Germany                             gert at greenie.muc.de
fax: +49-89-35655025                        gert at net.informatik.tu-muenchen.de