VoIP Mailing List Archives

[brent at texascountryt...]

Thought I would post this experience to the list so it's archived for
posterity... My company is deploying Asterisk-based PBX's to all of our
branch offices. Each office has 2 analog Voice lines and a fax line.
We didn't want to go to the expense of using TDM400's in the servers
(which run asterisk and Hylafax) so we opted for 2 X100P cards in each
box. So far they have worked fine at all but one office. The system at
the office in question would work perfectly for an entire day once it
was set up. The next morning, however, one of the 2 phone lines would
appear to be dead and the X100P would be in Red alarm. Plugging a phone
into the X100P's pass-through connection would show dial-tone on the
line, and the phone worked perfectly. It was as if the X100p lost it's
ability to see the audio on the line and nothing would revive it. Tried
restarting the zaptel module, rebooting the server completely, complete
power down, unplugging the phone line and even connecting up a phone
line simulator and moving the card to another server. The card never
works again. This went on for three days. Burned out an X100p every
night. I called the telco (Verizon) and they sent out a couple of guys
to run tests on the line, but found nothing. Their Demarc is properly
grounded and has surge suppression modules attached, the cable that runs
from their demarc to our punch-down block is in grounded metal conduit
and does not run near any power source. The cable that runs from the
punch-down block to the wall jack also does not run anywhere near
anything electrical, and everything is twisted pair all the way from the
wall jack to the demarc. To further eliminate the possibility of echo
or other noise, I ran twisted pair carrying both voice lines from the
wall jack to the server, approximately 3 feet in length. Now here is
where things get interesting... That 3 foot cable run passes behind a
21" monitor that was connected to the server. When the line tests
showed everything OK, I decided the monitor might be a long shot but I
could understand how the degaussing coil coil could possibly induce a
surge on the phone line if the monitor was somehow degaussing nightly,
so I unplugged the monitor's power cable and left everything else as it
was. So far so good. X100p #4 is still working this morning, so it
looks like the problem is solved. Hope this helps someone else later on.

Thanks,
Brent Davidson

[asterisk.org at sedwar...]

On Thu, 14 Feb 2008, Brent Davidson wrote:

[JonP at inline.net]

Quoting Brent Davidson <brent at texascountrytitle.com>: