[Asterisk-Users] Poor pstn line quality

[Rich Adamson]

Sorry, I missed your comment in the original post relative to hearing
noise on a analog set. If that static is being caused by opening or
shorting the pstn line (as in wind blowing cable around), then the
fxo modules "might" be sensing that has disconnect.



> That is exactly what I said in my post, the first line says that the static can
> be heard on standard analog phones plugged directly into the line.  I will
> check /proc/interrupts, but as I already stated, the lines have very poor
> quality as tested with standard analog phones.  However, the calls don't drop
> as they do with the fxo card.  how would I go about getting the cards on
> different interupts if they are on the same one?
> Tom
> 
> 
> Quoting Rich Adamson <radamson at routers.com>:
> 
> > > I just installed a new asterisk box with a wctdm with 4 FXO modules.  The
> > lines
> > > in the office have terrible static (using standard analog phones) and this
> > > static can obviously be heard through the asterisk box on the sipura sip
> > phones
> > > we installed.  This by itself would not be a problem as the office is used
> > to
> > > and doesn't mind (I don't know how) the static.
> > >
> > > However it appears that this really bad line quality is causing the fxo
> > ports to
> > > drop calls.  We tested all of the FXO ports in our office before we took
> > the
> > > box to install it, and it worked just fine... Here are the problems we are
> > > seeing:
> > >
> > > 1) Incoming calls, although immediate=no is set in zapata.conf the caller
> > hears
> > > one ring, and then when asterisk starts the simple switch, the caller hears
> > > static and dead air, as if asterisk had done an "answer()".  The caller
> > doesn't
> > > hear any more rings.  It takes asterisk about 3 seconds before it even
> > rings
> > > the internal sip phone, and then while the sip phone is ringing, until it
> > is
> > > answered the caller hears static and dead air. It seems as if the call has
> > been
> > > disconnected, or at least it will be very confusing for the customers of
> > this
> > > business, at any rate its unacceptable.
> > >
> > > 2) Outgoing and incoming calls: call quality is bad because of the static,
> > but
> > > randomly the zap channel that the call is on will hang up even though
> > neither
> > > side has hung up.  It seems like the poor line quality is somehow
> > simulating a
> > > "hangup" signal from the CO, and the fxo line is dropping the call.
> > >
> > > has anyone seen poor line quality cause the digium fxo modules to have
> > strange
> > > errors such as these?
> > >
> > > Thanks in advance for any replies/ideas/solutions (besides obviously
> > calling the
> > > phone company and telling them they suck)
> >
> > >From your description, it sounds more like a shared interrupt problem
> > (cat /proc/interrupts) then it does a pstn line problem.
> >
> > If it really is a pstn line problem, then plug the line into a ordinary
> > analog phone set and listen. If the pstn line is bad, you'll hear
> > the same noise on the analog set.
> >
> >
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> 
> 
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