[Asterisk-Users] Problem with Dutch PSTN-line on X100P

[The Traveller]

Yo all,

I have a problem with a Dutch (KPN) PSTN-line, connected to an X100P.
The call wil sound OK at first, but after 10-20 minutes, the audio will
start to crackle.  Soon after that, this crackle turns into a continuous
noise and the parties won't be able to hear eachother anymore.  It also
sometimes happens that the party on the TDM400P hears a very loud,
short-delay echo of themselves, best described as "talking in a
bathroom".  It very much sounds like very bad feedback, most of the
time.

The system concerned is a PIII-750 with an X100P and a TDM400P.
The problem occurs when a call is bridged between the X100P and
a port on the TDM400P.  Calls from the TDM400P to a remote IAX2-
connected box seem OK.

rxgain / txgain are at their default (0) for all interfaces and I'm
using the default echo-cancellation settings, with "echocancelwhenbridged"
enabled.  The PSTN-line concerned is a standard analog line from KPN, which
also has ADSL coming in over it.  The X100P is, ofcourse, connected
behind the splitter.  When I connect the X100P to an internal analog
port of a small legacy home-switch, the problem doesn't seem to occur,
either.

I'm using "opermode=1" for the X100P, but read on this list somewhere
that the chip used on the X100P is actually not the international version,
so this setting might not have any effect.  In this case, it doesn't
seem to matter if I use it or not.  There's no notable difference.

I'll probably investigate this problem further and play with the echo-
canceller and rxgain / txgain a bit.  Just curious if anyone else
is experiencing something similar and might have found a solution already.



   Grtz,

      Oliver