[Asterisk-Users] Poor pstn line quality

Tom tom at technerve.com
Sat Mar 26 13:17:29 MST 2005


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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