[asterisk-users] Call Quality / Echo / Problems

Barry Fawthrop
Mon, 02 Oct 2006 03:45:54 -0000

Hi all
I'm having a problem getting usable quality from my Asterisk setup.

*SETUP*
2 Ghz PC with 1 GB Ram with TDM 400p 1 x FXS to route to analog phones
in the house and 2 x FXO to receive calls and in the future faxes.
Gentoo Linux


Here is what I've done so far
(1) Moved theTDM 400p (FXS,   , FXO, FXO) to it's own interrupt (It was
sharing in the past)
cat /proc/interrupts
           CPU0
  0:   10236724          XT-PIC  timer
  1:        486          XT-PIC  i8042
  2:          0          XT-PIC  cascade
  5:   40694267          XT-PIC  wctdm    <============= 10:     196233
XT-PIC  eth0
 12:        225          XT-PIC  i8042
 14:     247177          XT-PIC  ide0
 15:         26          XT-PIC  ide1
NMI:          0
LOC:          0
ERR:          0
MIS:          0

(2) I'm running the latest kernel
 uname -r
2.6.17-

(3) I am running the latest Asterisk
Asterisk-1.2.12.1   Libpri-1.2.3  zaptel-1.2.8
I compiled Zaptel with  make clean ; make linux26 ; make install

(4) ztmonitor has become my friend
the Ring sends the VU meter off the chart, but the voice is below half way.
I have tried changing the rxgain, txgain  but that doesn't improve
much.  It raises the Volume and I can heard better.
But the "feedback" (What I hear of myself in my analog headset) is off
tone , too loud and poor

(5) ztspeed reports
Count: 254114  (Not sure if that is good or bad) ???

(6) zttest reports
--- Results after 474 passes ---
Best: 100.000000 -- Worst: 92.578125 -- Average: 99.713476

(7) I have even run ./fxotune
which generated /etc/fxotune.conf
3=3,0,0,0,0,0,0,0,0
4=4,0,0,0,0,0,0,0,0
Found
http://www.voip-info.org/wiki/view/Asterisk+fxotune
But the -d -b 3 doesn't work only -i and -s are allowed.


PROBLEM
The Call tone has a tin can sound  (too much highs and not enough lows,
for those with musical backgrounds)
The Volume has improved. It did sound like I was talking behind my hand
in front of my mouth, but not anymore.

The is a static HISSS that randomly comes and goes and gets so loud that
it drowns out whatever the calling party is trying to say.
It can be heard on both ends but very Loud on the FXS connected phone

Any Ideas What I can try next

Thanks All

Barry