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<div class=Section1>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>Hi<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>I have a particularly painstaking problem with ISDN
BRI. Currently I’m running Fedora Core 2. I was running Red
Hat 9 (2.4.20-8 kernel) but the problem remains the same. My problem is
as follows:<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>I have a BRI ISDN card installed which is based on the HFC
chipset. I have had no problem loading the card into the kernel with the
Hisax drivers (modprobe hisax type=35 protocol=2). Running dmesg shows
that the card was picked up fine. Also, I’ve had no problem
configuring the card within Asterisk. However, if I make a call from the
public operator to the ISDN card of the Asterisk box, it rings fine but when
the person on the Asterisk side picks up, they can perfectly hear the caller
from the outside, but the outside caller only hears a very scrambled or very
low quality voice.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>Our public operator uses ALaw. My guess is that
Asterisk has no problem in detecting the alaw encoded voice and decoding it
properly. Therefore the Asterisk caller can hear a perfect audio
quality. However, I believe that Asterisk does not encode the audio back
into alaw and therefore the outside caller hears a bad quality audio.
There is not problem with the call progress analysis which leads me to believe
that EuroISDN protocol is running fine. The problem probably lies within
the voice codecs used.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>Does anybody know how to fix this? Is the problem with
hisax? Is the problem with Asterisk? Should one use a different
driver like zaphfc or capi?<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>I’ve played a bit with zaphfc but have not been very
successful.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>Kind regards<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>Christiaan Brink<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
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