[asterisk-bugs] [DAHDI-linux 0017903]: Screech Sound (loud noise) heard every 100-200 calls in call centre environment

[Asterisk Bug Tracker]

A NOTE has been added to this issue. 
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https://issues.asterisk.org/view.php?id=17903 
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Reported By:                integratedvoip
Assigned To:                
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Project:                    DAHDI-linux
Issue ID:                   17903
Category:                   dahdi (the module)
Reproducibility:            random
Severity:                   major
Priority:                   normal
Status:                     new
JIRA:                        
Reviewboard Link:            
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Date Submitted:             2010-08-23 20:20 CDT
Last Modified:              2010-09-08 09:46 CDT
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Summary:                    Screech Sound (loud noise) heard every 100-200 calls
in call centre environment
Description: 
I have this happening on 3 clients now and it is getting to be a serious
problem.

These machines are connected to existing Phone systems via ISDN to record
calls and to directly connect SIP extensions.

On 2 machines the caller (connected to the existing phone system or via
SIP) hears the screeching sound (or loud noise) and then has to hangup the
call as it does not stop. On 1 machine the callee (on the other end of the
ISDN) hears the  screeching sound (or loud noise) and then has to hangup
the call as it does not stop.

I have the same configuration (i.e. connected to the Teclo and PABX to
record calls) on a number of clients and it works fine with large volumes
of over 20,000 calls per day on the same hardware.

I do not think this is a configuration issue, rather an incompatability
issues with certain PABX systems and we would need to find a workaround for
them.


This is causing me to pull me hair out. If someone can solve this one for
all machines I will make a minimum $500 support payment to the online
community of your choice.
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 (0126738) sruffell (administrator) - 2010-09-08 09:46
 https://issues.asterisk.org/view.php?id=17903#c126738 
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integratedvoip:  Are there any cases where the screech is heard that
doesn't run through the Asterisk system?  Since the callees always come in
through the existing PABX it is always involved, but it appears that when
internal users connected to the existing PABX hear the screeching (and the
recorder on the Asterisk box stops) the only thing really constant are
those PABX (i.e. if the asterisk box is only recording in that case, how is
it injecting audio into the call between the callee and the agent?).

Maybe the problem really lies with the PABX?  That could also be why you
don't have any problems with this setup at your other clients?

I'm assuming you have |PSTN| <--> |PABX| <--E1--> |Asterisk| <---> |Sip
end points| 

Issue History 
Date Modified    Username       Field                    Change               
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2010-09-08 09:46 sruffell       Note Added: 0126738                          
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