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<blockquote cite="mid:4683B4C6.7020600@coppice.org" type="cite">
<blockquote type="cite">
<pre wrap="">
So i've tried simulate fixed latency on my router (hold data for 200ms
from ATA to asterisk) and disable jb at all. FAX are OK. If jbenable =
yes - problem.
There is something wrong with jbenable or am I missing something?
Maybe there is somewhere activated PLC or some another filter?
whenever jbenable is turned on?
Codec is alaw
</pre>
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<pre wrap=""><!---->It is correct that a perceptual jitter buffer will play with the timing,
and that will break things like faxing. </pre>
</blockquote>
<br>
I need to investigate this, because without jitter there is no chance
to send fax on a little jittery network. (and there is no way to enable
or disable jitter or change jitter on the fly yet)<br>
<br>
On production system I have asterisk 1.2 patched with slavs
jitterbuffer implementation and digium 4port PRI. I've enabled SIP
adaptive jitterbuffer and with the same ATA reregistred to this
production system, i've send fax to my 1.4 with success. (Jun 28
16:16:04 VERBOSE[8475] logger.c: -- ***[JB LOG]*** adaptive
jitterbuffer created on channel Zap/32-1)<br>
<br>
Complete scenario: <br>
<br>
FAX -> ATA SIP -> Asterisk 1.2 adaptive jitter -> Zap PRI
---> TELCO SWITCH ---> Zap PRI asterisk 1.4 ---> iaxmodem. <br>
<br>
this work even though jitterbuffer is enabled on patched asterisk 1.2
which is almost the same as in 1.4. But there have to be some
differences which broken fax transmitions. <br>
<br>
<br>
<blockquote cite="mid:4683B4C6.7020600@coppice.org" type="cite">
<pre wrap="">You need to disable clever
jitter buffering algorithms when you need an unbroken stream. Typically
VoIP equipment will do this automatically when they hear FAX tones.
</pre>
</blockquote>
This is true for my testing ATA which is switching from adaptive to
fixed jitterbuffer. <br>
<br>
So the question is, why are frames modified when jitterbuffer is active
in 1.4 even though there is NO jitter (100mbit eth in lab environment).
I've disabled PLC in codecs.conf. <br>
<br>
Festr<br>
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