> 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.