Jim Thompson wrote:

On Sat, 07 May 2011 16:11:52 -0600, hamilton
wrote:

On 5/7/2011 4:03 PM, Jim Thompson wrote:
Question for your guys experienced in telephone circuits...

Every 30 minutes it looks like my on-hook voltage drops from 50VDC to
ZERO for a fraction of a second.

It happens so fast I can't get an accurate read on it... but the
auto-ranging DVM drops from "V" to "mV"

What is this all about?

...Jim Thompson

Some one may be working at the CO.

Moving a rack or something.

I was this when I got DSL.

My Caller ID box went berserk over this for days, then it stopped.

hamilton

This is deadly on 30 minute intervals. I even was able to set an
accurate pop-up on my calendar to make sure I watched the DVM ;-)

...Jim Thompson

Hook up a scope (digital?) put it on a relatively slow trace and trigger on
the drop with some pre-trigger time set.

--
Paul Hovnanian
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Fast wine, loose cars, old women.