Re: PLL Errors on 2501 -> PM3(Timing Probs?)

Kyle Platts (kwplat1@reliant.uswc.uswest.com)
Wed, 16 Jul 97 15:24:37 -0500

>Kyle, I have included the complete setup of the Adtran, but in =
reading the
other thread you were talking about timing, and the questions that =
were
never answered. Who supplies timing on a PRI, I assume the Telco =
has to
supply this timing, correct? Now I am beginning to wonder if this =
could be

The switch provides timing to the span on a PRI. The switch should =
get it's timing from either a stratum clock source or a tandem =
switch.=20

>having an effect on the timing for line1, with a PRI on line0 of =
the same

This could be. The T-1's should *each* take it's timing off of =
it's individual span. In other words, what happens on line 0 =
should have no affect on line 1, but I don't know if the PM3 was =
designed this way or not.....and it SHOULD!

>unit, I did change the Adtran here in NI/CLOCK SOURCE to NETWORK, =
so far I
haven't registered any errors in the past hour, and it seems to be =
a
stable connection, which doesn't mean much yet.=20

We need to have Livingston tell us how timing is taken care of in =
the PM3. It sounds like if the PM3 has a span on line 0 and it is =
getting clock from it, then line 1 seems to reference that same =
clock regardless of what's coming in. The fact that the telco saw =
slips tells you that there is definitely a timing problem on the =
span. I would call them back up and have them look now to see if =
the slips have gone away or not. You might also inquire as to who =
should be providing timing on the span (either you or them). I =
would guess that they are going to tell you that all timing is =
passed through, so you must provide the clock on the span.=20

>> Verify the settings again. The PLL alarm indicates that the =
Adtran
> cannot sync up to the selected clock source.
> Try changing the timing to loop and see what happens. =20

> I am assuming changing the timing to loop, would be changing =
from
INTERNAL to NETWORK, which I did.

Yep.

>Here is the exact config of the Adtran:
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
1) NI 1)Format:ESF
2)Code:B8ZS
3)YEL ALRM:ENA
4)XMIT PRM:OFF
5)CLOCK SOURCE:INTERNAL --> changed to NETWORK
6)BIT STUFFING:DISA
7)SET LBO:0.0
=20
I would change the line build out (LBO) to auto. This makes =
the CSU send out a signal that is the same strength as what is =
being received and helps to eliminate cross talk on the span.=20

The rest of the stuff looks good.

Kyle Platts
CSS-Tech
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