It appears to be a timing issue on the affected pbx’es by the zaptel driver. When I run the sudo /sbin/zttest when the MoH is garbled as well as when voice quality gets degraded it will respond with a value under 99%. From what I have found online, this driver is called on when using the Conference bridges and MoH.
This is what I am referring to:
forums.asterisk.org/viewtopic.ph … 75&start=0
last comment referring to test results when the quality is degraded:
Well, It appears that my timing issue was WITH my TDM400P, here’s the results of zttest:
— Results after 237 passes —
Best: 100.000000 – Worst: 91.613770 – Average: 99.483625
As you can see, there were significant drops in there that were causing my issues.
Here is the same tests on our pbx’es. Note 11 is suppose to be working as properly.
— Results after 57469 passes —
Best: 100.000 – Worst: 99.045 – Average: 99.954601, Difference: 99.992325
Which is expected as no quality issues reported there.
However on 14 and 16 i get much worse results:
— Results after 56114 passes —
Best: 100.000 – Worst: 70.218 – Average: 97.568579, Difference: 102.421440
— Results after 56165 passes —
Best: 100.000 – Worst: 47.164 – Average: 97.761109, Difference: 102.238612
the-asterisk-book.com/unstab … eetme.html
MeetMe conferences require a Zaptel interface to be installed in the Asterisk server; these provide a time source for synchronization of the participating channels. If no Zaptel interface is available, the ztdummy driver may be used.
MeetMe conferences always use the ulaw codec internally. The more conference participants use other codecs such as GSM or alaw, the higher the processor load due to transcoding.
Here is an end user report of the issue:
- The breaking up of the music is exactly like the breaking up of the voice signal.
a. While it might be they are disparate signals, common sense tells me that since the issue is so exactly the same for both the music and the voice, it’s hard to believe it’s not related or that the issue is not manifested by the same underlying problem. The same “breaking up” of the signal at the trailing end of a word or the music sounds exactly the same for voice and is so disruptive that is renders the conference call unusable.