asterisk users - Jan 2013 - echo from channel bank

I have several adtran 624 with 24 FXS ports hooked up to analog phones.  The
adtran is connected to asterisk via a channelized T1 into a digium TE820.  I
have hardware echo canceling enabled on all channels/spans, but there is still
echo on the lines for both calls out of the trunk, as well as station-to-station
calls.  I've checked the output of 'dahdi show channel x' and see
the echo turned on:

dozer2*CLI> dahdi show channel 149
Channel: 149
Description:
File Descriptor: 158
Span: 7
Extension: 98300326
Dialing: no
Context: from-zaptel
Caller ID:
Calling TON: 0
Caller ID subaddress:
Caller ID name:
Mailbox: none
Destroy: 0
InAlarm: 0
Signalling Type: FXS Kewlstart
Radio: 0
Owner: DAHDI/149-1
Real: DAHDI/149-1
Callwait: <None>
Threeway: <None>
Confno: -1
Propagated Conference: -1
Real in conference: 0
DSP: yes
Busy Detection: no
TDD: no
Relax DTMF: no
Dialing/CallwaitCAS: 0/0
Default law: ulaw
Fax Handled: no
Pulse phone: no
Gains (RX/TX): 0.00/0.00
Dynamic Range Compression (RX/TX): 0.00/0.00
DND: no
Echo Cancellation:
        128 taps
        currently ON
Wait for dialtone: 0ms
Actual Confinfo: Num/0, Mode/0x0000
Actual Confmute: No
Hookstate (FXS only): Onhook


I have echocanceller set to HWEC in dahdi/system.conf for all spans, and I have
echocancel=yes in chan_dahdi.cfg

I've tried reading some echo cancelation articles, but they seem to be
focused on trunks and not on stations.  Also, I'm not 100% sure if this is
an issue that I should focus on with asterisk, or if it's something I should
first take up with adtran?

I'm using dahdi 2.6.1, asterisk 10.10.0.

Thanks in advance,
-Justin
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It sounds to me like you should first discuss it with adtran. The standard echo
cancellation for Asterisk have a hard time cancellingecho generated at the far
end, especially if the echo tail/delay is notminimal.?

If adtran can not solve the problem at their end, you can use a server-side echo
cancellation that can handle long echo tail. One option is PBXMate.



________________________________
 From: Justin Killen <jkillen at allamericanasphalt.com>
To: Asterisk Users Mailing List - Non-Commercial Discussion <asterisk-users
at lists.digium.com>
Sent: Tuesday, January 8, 2013 12:17 AM
Subject: [asterisk-users] echo from channel bank
 

 
I have several adtran 624 with 24 FXS ports hooked up to
analog phones. ?The adtran is connected to asterisk via a channelized T1 into a
digium TE820. ?I have hardware echo canceling enabled on all channels/spans,
but there is still echo on the lines for both calls out of the trunk, as well
as station-to-station calls.? I?ve checked the output of ?dahdi
show channel x? and see the echo turned on:
?
dozer2*CLI> dahdi show channel 149
Channel: 149
Description:
File Descriptor: 158
Span: 7
Extension: 98300326
Dialing: no
Context: from-zaptel
Caller ID:
Calling TON: 0
Caller ID subaddress:
Caller ID name:
Mailbox: none
Destroy: 0
InAlarm: 0
Signalling Type: FXS Kewlstart
Radio: 0
Owner: DAHDI/149-1
Real: DAHDI/149-1
Callwait: <None>
Threeway: <None>
Confno: -1
Propagated Conference: -1
Real in conference: 0
DSP: yes
Busy Detection: no
TDD: no
Relax DTMF: no
Dialing/CallwaitCAS: 0/0
Default law: ulaw
Fax Handled: no
Pulse phone: no
Gains (RX/TX): 0.00/0.00
DynamicRangeCompression
(RX/TX): 0.00/0.00
DND: no
Echo Cancellation:
??????? 128 taps
??????? currently ON
Wait for dialtone: 0ms
Actual Confinfo: Num/0, Mode/0x0000
Actual Confmute: No
Hookstate (FXS only): Onhook
?
?
I have echocanceller set to HWEC in dahdi/system.conf for
all spans, and I have echocancel=yes in chan_dahdi.cfg
?
I?ve tried reading some echo cancelation articles, but
they seem to be focused on trunks and not on stations. ?Also, I?m not
100% sure if this is an issue that I should focus on with asterisk, or if it?s
something I should first take up with adtran?
?
I?m using dahdi 2.6.1, asterisk 10.10.0. 
?
Thanks in advance,
-Justin
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