[Asterisk-Users] PSTN Incoming call on real line disrupts VoIPcall over DSL circuit - EXPLAINED

[Alexander Lopez]

DSL works by using the frequencies above 4k that were unused in POTS loops of yesterday. Load Coils, Bridge Taps, and DC taps are all devices added to lines to increase their reach and stability, unfortunately, they are DEADLY for DSL. Other problems can effect DSL service, and cause it to be 'flaky'.

1	Temperature, in Florida the large black cables are constantly beaten down by the sun, if the temperature change is gradual, the DSL modem, (Modulator/ Demodulator) can quickly and quietly 're-train' the line for the changes. Rapid changes may cause the carrier to drop, (IE rain storm, cools off the cable quickly and changes the resistance on the loop)

2	Shorts or grounds, When the line 'rings' it sends voltage down the line if there is a short, or a ground open somewhere it changes the properties on the line causing havoc with the line.

After reading this post, I feel that the problem is, a. Bad Westell, b. Bad loop.

Bell will run a loop test from the DSLAM 'out' to your site. While they are doing this, call from another phone to make sure the test fails, or shows what the problem is.



> -----Original Message-----
> From: asterisk-users-bounces at lists.digium.com [mailto:asterisk-users-
> bounces at lists.digium.com] On Behalf Of Hadar Pedhazur
> Sent: Tuesday, May 09, 2006 2:18 PM
> To: Asterisk Users Mailing List - Non-Commercial Discussion
> Subject: Re: [Asterisk-Users] PSTN Incoming call on real line disrupts
> VoIPcall over DSL circuit - EXPLAINED
> 
> Juergen K. Zick wrote:
> > HI,
> >
> > well, that was what I expected in my posting yesterday. For me, your
> > wiring looks strange. Here in Germany, we have "spiltters" connected to
> > the incoming line which have two outputs: A high pass filter output for
> > the DSL signal and a low pass output with DC  pass-through for the POTS
> > signal. the DSL output is being connected to the DSL-modem and the POTS
> > output will feed your internal POTS wiring.
> 
> The only jack that has both a phone and the DSL connector indeed has a
> splitter on it, provided by Bellsouth.
> 
> > Therefore, there is _NO_ filter needed on each POTS outlet, because
> > there is nothing to be filtered out on your internal line anymore.
> 
> You may be correct. I am definitely _not_ familiar enough with DSL.
> However, 5 years ago, I had a DSL line in my apartment, and I was
> specifically told by the installation tech that I needed a filter on
> _any_ jack that had a real phone connected to it. That may not have been
> necessary, or perhaps isn't necessary any longer, or perhaps varies by
> provider, but that's what I was told at the time, and that's what I did
> (with no problems).
> 
> The filters on the phone jacks that didn't have the modem connected were
> not splitters, just single filters.
> 
> > Seen from my German wiring knowlegde, your cabling is wrong and causes
> > the interruptions on the DSL service.
> 
> That's definitely possible, just not my personal (single point!)
> experience.
> 
> > Don`t you have something like a "spiltter" available ? It should be the
> > _ONLY_ filter on your incoming line and then the DSL-modem and the POTS
> > phone should be connected to it ...
> 
> OK, it would be easy for him to remove the other filters temporarily and
> test again.
> 
> Thanks!
> 
> > --Jürgen
> 
> >> Replying to my own post (and my most recent follow-up). I have now
> >> confirmed 100% that the DSL modem gets a _new_ IP address every time
> >> his "real" phone gets answered, or hung up! This (of course) disrupts
> >> the audio coming from to him, since the sending machine (Asterisk in
> >> my case), no longer has the correct IP address to send to him.
> >>
> >> I lowered his registration from the default 1 hour to 1 minute, so
> >> after we're disconnected, I can see that he's re-registering with a
> >> new IP address, each and every time :-(.
> >>
> >> I told him to call Bellsouth and ask about a Static IP address, but I
> >> don't know if they offer it, or how much they charge.
> >>
> >> While this one isn't "solved", it's at least "explained".
> >>
> >> Thanks to everyone who responded!
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