DSU/CSU units

GBURG::ENGER (enger%gburg.decnet@bluto.scc.com)
22 Sep 87 12:33:00 EST

We have a couple of T1 circuits, but the equipment on the ends functions
as its own "DSU", so all that is required are outboard CSU units.

We use Digital Link Corp. Model 551C.
I think we have had three blow out so far. And a fourth leaked span power
to its chasis! It turns out they had problems with the physical construction
of the units. A bolt came very close to the circuit board and often shorted
or arcked during electrical storms, etc. The factory supposedly installed
an engineering modification (cutting the excess off of the bolts probably)
to lower the likelyhood of lightning damage. When one of the units came back
from getting "the fix", its Percent Error Free Seconds display simply counted
down constantly.

The Error Free seconds display is a nice feature. It keeps an "objective"
eye on the status of the line. Makes it real easy to point the finger at the
phone company. Other than span power outages due to lightning blowing the
CO fuses, the only problem I have ever had with the T1s was a bad punch at
the undergroud, and the CSU EFS display showed it as an excessive error rate,
and indicated which direction the problem was in. The local operating
company fixed it promptly, no questions asked. They took one look at the
display on the csu, and went to work on the span.

If you wish to contact them, Digital Link is in Sunnyvale, Ca
Phone number 408-745-6200

Good luck,

From: GBURG::ENGER "Robert M. Enger {CONTEL Fed. Sys} (301)840-4906" 22-SEP-1987 12:42
Subj: RE: [TCP/IP Mail From: <weidlich@ludwig.scc.com>] ludwig non-functional when net is down

I don't "think" the ypbind has anything to do with the iebark reset.
I'll check into it.
 (I think rebooting the machine is what cleared your problem??)

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