cisco echo cancellation problem

Unanswered Question
Oct 2nd, 2010

Dear All

I have problem with echo on my cucm system

I have call manager 8.0 with a 2 E1 pstn connectivity (vwic2-2mft)

when my ip phone users calls pstn , the hear their voice (echo)

i played with variuos items like input gain and output attenu and also erl but not effective

i want to know how can i eliminate the echo and make everyone free!!

please hint me a solution by the eay i read many cisco documents but nothing happen!

I have this problem too.
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Christopher Graham Sat, 10/02/2010 - 16:51

Are your users using a head set, or the phone's handset.  Sometimes there can be an impedance mismatch between the phone and a headset which can cause echo.

If they are using the handset, make sure there are no clocking issues on the E1 controller (show controllers E1).  Clocking issues can cause the ECANs on the gateway to not properly engage.

I'm assuming you are using a Cisco voice gateway, is this correct? (2800, 3800, 2900, 3900, etc)  If so, what is your config for the E1 voice ports?  What is the 'echo-cancel coverage' set to?  What IOS version are you running?

hanimolani Sun, 10/03/2010 - 11:31

Thank you for your reply

by the i have simple config on my e1 controller

the config is :

controller e1 0/0/0

clock soure line

pri-group timeslot 1-31

framing no-crc

the cisco voice gateway is cisco 2811 with pvdm-64 and ios is 12.4 (24) T4 (almost the last one)

right now i set my echo coverage into 64ms

but in some phones i have still my echo

please help

Steven Holl Mon, 10/04/2010 - 08:50

Post output of:

sh controller e1

Get multiple outputs of this, ideally during while the issue occurs, but get it anyway if you can't get a call with the issue just yet:

sh call active voice echo sum

Also, grab this one if you can get a call up with it and can get the ID of the call from the ANI/DNIS and 'sh call active voice br':

sh call active voice echo id

Put your input gain on the voice-port to 0, too.  And make sure the issue is seen on the phone handset, like Chris mentioned.

After this, we can look at some things.

hanimolani Tue, 10/05/2010 - 23:40

outer#show controllers e1
E1 0/0/0 is up.
  Applique type is Channelized E1 - balanced
  Cablelength is Unknown
  No alarms detected.
  alarm-trigger is not set
  Version info Firmware: 20100222, FPGA: 13, spm_count = 0
  Framing is NO-CRC4, Line Code is HDB3, Clock Source is Line.
  Data in current interval (856 seconds elapsed):
     0 Line Code Violations, 0 Path Code Violations
     32 Slip Secs, 0 Fr Loss Secs, 0 Line Err Secs, 0 Degraded Mins
     32 Errored Secs, 0 Bursty Err Secs, 0 Severely Err Secs, 0 Unavail Secs
  Total Data (last 24 hours)
     8195 Line Code Violations, 160 Path Code Violations,
     3244 Slip Secs, 0 Fr Loss Secs, 0 Line Err Secs, 0 Degraded Mins,
     3244 Errored Secs, 0 Bursty Err Secs, 0 Severely Err Secs, 22 Unavail Secs
E1 0/0/1 is up.
  Applique type is Channelized E1 - balanced
  Cablelength is Unknown
  No alarms detected.
  alarm-trigger is not set
  Version info Firmware: 20100222, FPGA: 13, spm_count = 0
  Framing is NO-CRC4, Line Code is HDB3, Clock Source is Line.
  Data in current interval (859 seconds elapsed):
     0 Line Code Violations, 0 Path Code Violations
     32 Slip Secs, 0 Fr Loss Secs, 0 Line Err Secs, 0 Degraded Mins
     32 Errored Secs, 0 Bursty Err Secs, 0 Severely Err Secs, 0 Unavail Secs
  Total Data (last 24 hours)
     0 Line Code Violations, 31 Path Code Violations,
     3244 Slip Secs, 0 Fr Loss Secs, 0 Line Err Secs, 0 Degraded Mins,
     3244 Errored Secs, 0 Bursty Err Secs, 0 Severely Err Secs, 0 Unavail Secs
Router#


here is the output of my e1 controller
please follow it.because the issue is not solved
Steven Holl Wed, 10/06/2010 - 06:22

You have slips on your E1, which will causes issues with the ECAN, since it disrupts the return audio coming back and can't compare it to the original audio in the tail buffer.  This is a misconfiguration; you always need to select a clock to spin the DSP clock off of when doing a voice TDM circuit, otherwise you will have slips.

Are both of these circuits to the same provider?  Are they the only E1s terminating on this box?  If the answers are both yes:

network-clock-select 1 e1 0/0/0

network-clock-select 2 e1 0/0/1

Then issue 'clear counters' from exec mode.

If you answered no to either of the above questions, describe the E1 terminations in more details and we can figure out the best clocking configuration for you.

Monitor for echo after resolving your slips, and ensure that output shows no slips from here.  If you still have echo issues, and your input gain is set to 0, then proceed with:

Get multiple outputs of this, ideally during while the issue occurs,  but get it anyway if you can't get a call with the issue just yet:

sh call active voice echo sum

Also,  grab this one if you can get a call up with it and can get the ID of  the call from the ANI/DNIS and 'sh call active voice br':

sh call active voice echo id

hanimolani Mon, 10/11/2010 - 07:47

my bothe e1 lines are from same provider and just e1 termination

i have inserted the the commands that you mentiond for me

network-clock-select 1 e1 0/0/0

network-clock-select 2 e1 0/0/1

but also i have to use this command alsi "network-clock-participate wic 2" because its mandatory

after i inserted the above two commands i have also shut and not shut for my controller e1

and also clear the counters

here are also my output of your needed commands:

the output of the

Router#show call active voice echo 0x1215
ACOM=35  ERL=35
Echo canceller control words=6C 5000
Bypass=OFF  Tail=64  Residual ecan=Comfort noise
Freeze=OFF  Modem tone disable=Ignore 2100Hz tone
Worst ERL=6  High level compensation=OFF
Max amplitude reflector (in msec)=25
Ecan version = 9183


Router#show call active voice echo 0x1214
ACOM=28  ERL=28
Echo canceller control words=6C 1000
Bypass=OFF  Tail=64  Residual ecan=Comfort noise
Freeze=OFF  Modem tone disable=Ignore 2100Hz tone
Worst ERL=6  High level compensation=OFF
Max amplitude reflector (in msec)=33
Ecan version = 9183

thank you for  your follow

best regards

Steven Holl Mon, 10/11/2010 - 07:56

That output looks good.  ERL is high and the tail buffer length is stable.  Monitor for echo from here.

hanimolani Mon, 10/11/2010 - 08:50

dear steven


thank you for your follow by the way how should I monitor for echo?

i am just asking people if they have or not..you mean that?

Steven Holl Mon, 10/11/2010 - 08:59

Yeah, the only real way to be sure if echo is still occurring is to have your users let you know.

If this is CUCM, you could install the QRT button on their phone and they can use that to report if they have a call with Echo. Then you can run a QRT report and see if people complain about echo still.

hanimolani Mon, 10/11/2010 - 09:15

dear steven

i am doing now qrt and waiting for result

by the way i configure input gain to 0 and also output atten to 0

if the someone complain about this issue i will let you know by this community

thank you again

hanimolani Tue, 10/12/2010 - 02:25

steven and all other guys

i have two echo today here are the values

please give me any hint or idea

Router#show call active voice echo 0x1833
ACOM=7  ERL=7
Echo canceller control words=6C 5000
Bypass=OFF  Tail=64  Residual ecan=Comfort noise
Freeze=OFF  Modem tone disable=Ignore 2100Hz tone
Worst ERL=6  High level compensation=OFF
Max amplitude reflector (in msec)=9
Ecan version = 9183



Router#show call active voice echo 0x16CA
ACOM=30  ERL=30
Echo canceller control words=6C 5000
Bypass=OFF  Tail=64  Residual ecan=Comfort noise
Freeze=OFF  Modem tone disable=Ignore 2100Hz tone
Worst ERL=6  High level compensation=OFF
Max amplitude reflector (in msec)=10
Ecan version = 9183
Router#show call active voice echo 0x16CF
Error, data for call 16CF is not available
Router#
Steven Holl Tue, 10/12/2010 - 06:15

At this point you should open a TAC case to investigate this further.  Likely the next step is to get a PCM capture during a call with echo.

hanimolani Tue, 10/12/2010 - 06:33

how can i have pcm capture and what shoudl find out?

do you have not any idea about input gain and output attenu ?

right now both is set to zero

Steven Holl Tue, 10/12/2010 - 07:48

Lowering gain or increasing output attenuation just effects the ERL.  The ERL should be around 15-20 for it to effectively eliminate echo.  To verify if ERL is the culprit, you need to get the output of 'sh call active voice echo id ' for the call with echo *while the user is talking and hearing echo* since the command is an instantaneous measurement.

You can get a PCM capture for an intermittent issue with the following script:

https://supportforums.cisco.com/message/3176989#3176989

But you really need to open a TAC SR at this point.  It's going to get into low-level echo troubleshooting.  We need to look at the ERL when the issue occurs and measure the tail length of the echo tail.

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