[Asterisk-Users] TDM Echo issue

[Sascha Ferley]

Hi, 

 

I am running into a issue with a TDM04B card. When dialing out I get an
noticeable (extreme to some people) echo, in that I can hear myself. The
person on the other line doesn't hear any echo and the call sounds perfect
to them. 

 

I checked and tested a few things as per suggestions on voip-info.org with
RX/TX gain and using ztmonitor. I adjusted the 

rxgain=10.5 txgain=-4.5 and it doesn't seem  to do to much to eliminate me
hearing myself on the phone. I can't go any lower on txgain then -5.5 before
the call doesn't go through any more. If I change the txgain to above 0 the
echo gets even worse.  

 

I am using Cisco 7960 phones and calling IP to IP is perfect; the echo
occurs only when going out the zap channels to the PSTN. Below is the
relevant zapata.conf file.  I also checked the /proc/interrupts file and the
interrupts seem normal (see below). 

 

If anyone has any other suggestion, please let me know,

 

Thanks

 

Sascha

 

 

### /proc/interrupts ############

           CPU0              CPU1

  0:       62224232        62229547        IO-APIC-edge             timer

  1:       0                      3                      IO-APIC-edge
keyboard

  2:       0                      0                      XT-PIC
cascade

  4:       0                      5                      IO-APIC-edge
serial

  8:       0                      1                      IO-APIC-edge
rtc

 14:      0                      2                      IO-APIC-edge
ide0

 18:      556800            715820            IO-APIC-level
libata

 20:      562694111      681819012      IO-APIC-level             wctdm

 53:      24008833        8                      IO-APIC-level
eth0

NMI:    0                      0

LOC:   123628432      123628430

ERR:    0

MIS:   0

 

 

##### /etc/asterisk/zapata.conf #########

;

; Zapata telephony interface

;

; Configuration file

 

[trunkgroups]

 

[channels]

 

language=en

context=from-pstn

signalling=fxs_ks

rxwink=300              ; Atlas seems to use long (250ms) winks

;

; Whether or not to do distinctive ring detection on FXO lines

;

;usedistinctiveringdetection=yes

 

usecallerid=yes

hidecallerid=no

callwaiting=yes

usecallingpres=yes

callwaitingcallerid=yes

threewaycalling=yes

transfer=yes

cancallforward=yes

callreturn=yes

echocancel=yes

echocancelwhenbridged=yes

;echotraining=800

echotraining=yes

rxgain=0.0

txgain=0.0

group=0

callgroup=1

pickupgroup=1

immediate=no

 

;faxdetect=both

faxdetect=incoming

;faxdetect=outgoing

;faxdetect=no

 

;Include genzaptelconf configs

#include zapata-auto.conf

 

;Include AMP configs

#include zapata_additional.conf

 

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