[Asterisk-Users] How to ensure that software echo cancellation is on?

[Don Murray]

Thanks for the reply.

If I change something to either zaptel.conf or zapata.conf I do the 
following:
- shut down asterisk with a "stop now"
- do a "ztcfg" which I believe refreshes the zaptel modules
- restart asterisk

Should I unload the module and reload by hand?

Actually, since I set up the files as below, I have rebooted the machine 
(involuntarily, we had a power failure) and the echo status I show is 
from after the reboot, so it can't be a "not started from a deep enough 
level" issue...

This is why I was wondering whether something strange is happening in 
that some flags in the zapata.conf file just aren't getting set in the 
system.  Its frustrating.  Does anyone have a proven zapata.conf for a 
T1 setup that I can use as an example maybe?  Any other way to test echo 
status (like if its really compiled into the module).

Thanks,
Don

jjones at quiddesign.com wrote:

> Per your readout it is off. A normally operating channel would look  
> something like
>
> Echo Cancellation: 128 taps, currently ON
>
>
> You are restarting asterisk as you make changes and not just  
> reloading right:)
>
> On Jun 2, 2005, at 3:40 PM, Don Murray wrote:
>
>>
>> I have appended my /etc/asterisk/zapata.conf and my /etc/ zaptel.conf 
>> files.  I am running Asterisk 1.0.7 on a P3 800 MHz  system in an 
>> office with around 20 sip phones.  We are using a  Digium Wildcard 
>> TE110P that is connected to a T1 line with 8 lines  enabled. We have 
>> been experiencing irritating echo on the sip phone  side when local 
>> lines are called.
>> After reading a lot of echo related threads, I think I understand  
>> the 4-wire to 2-wire cause of this echo.  I have noticed that when  
>> calling long distance and with some cell phones there is no echo,  
>> which is consistent with a system that has echo cancellation on the  
>> destination end.
>>
>> So, I've been trying to enable software echo cancellation to see if  
>> it will improve the situation.  If you look down to see my  
>> zapata.conf file, you will see I've tried to set echocancel and  
>> echocancelwhenbridged, and that I've also mucked around with  
>> echotraining.  None of these appear to be doing anything.
>> However, I *think* this is because they are not being enabled  
>> properly, because when I try to see the details of an active zap  
>> channel (see zap show channel command) it says "Echo Cancellation:  0 
>> taps unless TDM bridged, currently OFF".   I'm not sure if I'm  doing 
>> this debugging right, so I wanted to ask people both :
>>
>> (a) am I enabling echocancel correctly?  I've heard that sometimes  
>> these parameters can behave differently depending on the order they  
>> appear in the file??
>>
>> (b) am I doing the right thing to detect if echo cancellation is  
>> on?  Whats the righ tway to do that?
>>
>> btw, I have rebuild my zaptel src with "AGGRESSIVE" cancellation  
>> enabled, with MMX enabled and with MARK2 cancellation enabled.
>>
>> Any advice appreciated!
>>
>> Thanks,
>> Don
>>
>>
>>
>> asterisk1*CLI> zap show channel 8-1
>> Channel: 8CLI>
>> File Descriptor: 32
>> Span: 1
>> Extension:
>> Dialing: no
>> Context: from-pstn
>> Caller ID string: 520xxxxxxx
>> Destroy: 0
>> InAlarm: 0
>> Signalling Type: PRI Signalling
>> Owner: <None>
>> Real: <None>
>> Callwait: <None>
>> Threeway: <None>
>> Confno: -1
>> Propagated Conference: -1
>> Real in conference: 0
>> DSP: no
>> Relax DTMF: no
>> Dialing/CallwaitCAS: 0/0
>> Default law: ulaw
>> Fax Handled: no
>> Pulse phone: no
>> Echo Cancellation: 0 taps unless TDM bridged, currently OFF
>> PRI Flags:
>> PRI Logical Span: Implicit
>> Actual Hookstate: Onhook
>> asterisk1*CLI>
>>
>>
>> === zapata.conf
>>
>> [channels]
>> language=en
>>
>> context=from-pstn
>> switchtype = national
>> signalling = pri_cpe
>> group = 0
>> channel => 1-8
>> faxdetect=both
>> ;;echocancel=yes
>> ;;echotraining=yes
>> ;echocancelwhenbridged=yes
>> echocancel=256
>> ;echotraining=800
>>
>>
>> === zaptel.conf
>>
>> loadzone        = us
>> defaultzone     = us
>>
>> span=1,1,0,esf,b8zs
>> bchan=1-8
>> dchan=24
>>
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>
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