Asterisknow 1.5.0 Dahdi busydetect vietnam loadzone debug

Hi all,
Here is a problem that need professional help, and I’m very happy if anyone can help. At the same time I’d like to post useful info about what I have found so far.

Problem: Asterisk is not detecting busy signal, for example when a analogue PSTN user hang up. This is a problem in voicemail maybe other places. The result is that all voicemail messages are 120sec long, with busy beep.

Vietnam signal measuered with
Frequency: 447hz
On 0,36sec
Off 0,36sec

This seem to be close to China configuration:
DAHDI_TONE_BUSY, “450/350,0/350” },


  1. How do I select china config?
  2. How can I confirm that it is actually being used?
  3. How can I get debug information about busy detect?

To select china config I have tried:

  • manually Change loadzone and defaultzone in /etc/dahdi/system.conf. After that I run dahdi_cfg and restart (amportal restart).

if I run dahdi_genconf, then loadzone and defaultzone is back to “US”.

I’m I doing something wrong?

To “fix” this I edited /usr/sbin/dahdi_genconf by replacing my $lc_country = ‘us’; with my $lc_country = ‘cn’;
Then I can run dahdi_genconf, and get correct loadzone in system.conf.

But still the system cannot detect busy :frowning:

I have found that debug can be activated on dahdi modules by:
echo 1 >/sys/module/dahdi/parameters/debug
cat /sys/module/dahdi/parameters/debug

But I don’t get any debug messages. Where are they?


I really need help with this… please :smile: