[lug] OT: ATT Broadband service interruptions?

Nate Duehr nate at natetech.com
Fri Nov 1 15:40:44 MST 2002

RF tuning problem?  Perhaps an RF level problem, but if it's going out
of tune (off-frequency) the cable operator has some SERIOUS problems.

I think what you're saying is that most cable modems like to see their
incoming levels at a reasonable amplitude... and yes, attenuators are
sometimes used to pad the signal if you're *very* close to the head-end.

A more "common" problem is simply the quality of the coax being used
indoors and where it runs in the house... a "quick fix" for many cable
modem problems is to throw out the crap coax the cable installer used to
connect the modem and replace with an appropriate length of good quality
75-ohm stuff and good connectors.


On Thu, 2002-10-31 at 10:34, Fred Robinson wrote:
> Can't say I've seen this exact problem, but it sounds like an RF tuning
> problem in your cable plant.  The RF is ranging which is causing your modem
> to lose connectivity.  I would call AT&T and tell them there is an RF
> problem in your neighborhood.  And it is possible that it is an isolated
> problem with your cable run and your cable run may require more attenuation
> to "tune" it properly.
> And yes, your modem can be rebooted from the headend (from the Cable Modem
> Termination System, CMTS), but that's not what's happening here.
> Fred Robinson
> Operator, SIPFusion
> 558 Copperdale Ln.
> Golden, CO 80403
> fred.robinson at sipfusion.com
> office: 303.642.8061
> mobile: 720.272.5201
> -----Original Message-----
> From: lug-admin at lug.boulder.co.us [mailto:lug-admin at lug.boulder.co.us]On
> Behalf Of John Dollison
> Sent: Monday, October 28, 2002 10:39 PM
> To: lug at lug.boulder.co.us
> Subject: [lug] OT: ATT Broadband service interruptions?
> This isn't exactly Linux related, but you guys are more computer-savvy than
> 95% of the local Windows users.....
> I'm on the AT&T Broadband service, and lately I've been having lots of
> problems connecting to various websites.  I thought I was having a hardware
> problem with my cable modem, but I just got off the chat-line with AT&T's
> support guy, and he says it's a Network Operations Center problem.  Normally
> I'd believe him, but this problem seems odd to me.  I'd like some feedback
> from you guys.
> Here are the details:
> My home setup is two computers (both are dual-boot Linux and Windows)
> connected to an SMC Barricade router, which connects to my cable modem.
> I have an RCA DCM215 cable-modem which I've leased from AT&T for about 2
> years now.  I noticed a long time ago that it will go into a hard-reset if
> you bump it, exactly as if someone had pulled the power and then plugged it
> back in again - all the lights go out, then come back on, one-by-one, until
> the signal is re-aquired and service is restored.  So I always figured there
> was a loose wire inside, but never bothered to call tech support about it.
> (Also, I'm on a TrippLite UPS, so I believe my 115V power is stable.)
> Over the past week or two, the problem has started occuring on its own,
> without any "bumping" of the modem; but it seems to happen especially when
> I'm trying to use Outlook to access my various e-mail accounts and
> newsgroups.  It's now occuring several times a day.  I've never heard of any
> software command that AT&T (or anyone else) could send to make the modem do
> a hard reset, so I figured the modem was just getting ready to die on me.  I
> got on the AT&T support website and talked to one of their reps, but he
> insists it's not a hardware problem.  I asked if their network was under
> attack, and he said no.  He did a tracert to my IP, and says there's a long
> delay at my end, indicating a problem in the local network, but NOT at my
> modem or PC.
> So what gives?  Has anyone else seen problems on ATT Broadband?
> Thanks,
> John D
> .
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Nate Duehr, nate at natetech.com

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