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[asterisk-users] noisy analog lines

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asterisk at iancoetzee...
Guest

Posted: Fri Apr 25, 2008 3:06 am Post subject: [asterisk-users] noisy analog lines

Hi all

I have a small problem here.

We are running Asterisk 1.4.18 and libpri 1.4.3 (how can I check the
zaptel version again?) on an Intel core 2 duo 1.6Ghz, 2GB ram under
Ubuntu server.

We have 4 analog line coming into the box via a TDM 800 wildcard with
echo cancel module and quad fxo modules.

The server has been running smoothly with almost no problems for awhile now.

Recently I started picking up problem with the voice clarity on our end,
it sounds like a mobile going through a low signal patch. I asked the
person on the other end and they can hear me loud and clear.

I bumped the txgain up a notch a while back, can it be because of this?

I ran a top and saw that the server only have about 16Mb free ram, can
this be a possible cause?

My zapata.conf and zaptel.conf are below.

Thanks in advance
Ian

Quote:

# less /etc/zaptel.conf
# Autogenerated by /usr/sbin/zapconf on Fri Feb 29 16:12:07 2008 -- do
not hand edit
# Zaptel Configuration File
#
# This file is parsed by the Zaptel Configurator, ztcfg
#
# Span 1: WCTDM/0 "Wildcard TDM800P Board 1" (MASTER)
fxsks=1
fxsks=2
fxsks=3
fxsks=4
# channel 5, WCTDM/0/4, no module.
# channel 6, WCTDM/0/5, no module.
# channel 7, WCTDM/0/6, no module.
# channel 8, WCTDM/0/7, no module.

# Global data

loadzone = za
defaultzone = za
# less /etc/asterisk/zapata.conf
[trunkgroups]
; define any trunk groups

[channels]
;hardware channels

;default
;groep nommers en rede
; 1 => Landlyn
; 2 => Selfoon

; Span 1: WCTDM/0 "Wildcard TDM800P Board 1" (MASTER)
;;; line="1 WCTDM/0/0"
signalling=fxs_ks
callerid=asreceived
context=incoming_calls
group=2
busydetect=yes
usecallerid=yes
hidecallerid=no
callwaiting=no
threewaycalling=yes
transfer=yes
echocancel=yes
pulsedial=no
callprogress=yes
busycount=5
subscribecontext=GXP_BLF
overlapdial=no
toneduration=200
txgain=10.0
rxgain=10.0
channel => 1

;;; line="2 WCTDM/0/1 FXSLS"
signalling=fxs_ks
callerid=asreceived
context=incoming_calls
group=1,2
busydetect=yes
usecallerid=yes
hidecallerid=no
callwaiting=no
threewaycalling=yes
transfer=yes
echocancel=yes
pulsedial=no
callprogress=yes
busycount=5
subscribecontext=GXP_BLF
txgain=10.0
rxgain=10.0
overlapdial=yes
channel => 2

;;; line="3 WCTDM/0/2"
signalling=fxs_ks
callerid=asreceived
context=incoming_calls
group=1
busydetect=yes
usecallerid=yes
hidecallerid=no
callwaiting=no
threewaycalling=yes
transfer=yes
echocancel=yes
pulsedial=no
callprogress=yes
busycount=5
subscribecontext=GXP_BLF
txgain=10.0
rxgain=10.0
overlapdial=yes
channel => 3

;;; line="4 WCTDM/0/3"
signalling=fxs_ks
callerid=asreceived
context=incoming_calls
group=1
busydetect=yes
usecallerid=yes
hidecallerid=no
callwaiting=no
threewaycalling=yes
transfer=yes
echocancel=yes
pulsedial=no
callprogress=yes
busycount=5
subscribecontext=GXP_BLF
txgain=20.0
rxgain=10.0
overlapdial=yes
channel => 4

tzafrir.cohen at xorco...
Guest

Posted: Fri Apr 25, 2008 8:03 am Post subject: [asterisk-users] noisy analog lines

(Not a real answer to your qustion, but still)

On Fri, Apr 25, 2008 at 10:06:08AM +0200, Ian wrote:

Quote:

Hi all

I have a small problem here.

We are running Asterisk 1.4.18 and libpri 1.4.3 (how can I check the
zaptel version again?) on an Intel core 2 duo 1.6Ghz, 2GB ram under
Ubuntu server.

The current version of the loaded Zaptel modules (works as of kernel
2.6.12 or so) -

cat /sys/module/zaptel/version

The version of the installed module:

modinfo zaptel | grep ^version

Quote:

I ran a top and saw that the server only have about 16Mb free ram, can
this be a possible cause?

Generally, no. But where exactly do you see that?

tzafrir at boole:~$ top -b -n 1 | head -n 5; free
top - 15:59:54 up 51 days, 7:12, 10 users, load average: 0.00, 0.00, 0.00
Tasks: 132 total, 1 running, 124 sleeping, 7 stopped, 0 zombie
Cpu(s): 0.7%us, 0.6%sy, 0.2%ni, 92.2%id, 6.1%wa, 0.0%hi, 0.0%si, 0.0%st
Mem: 505468k total, 497452k used, 8016k free, 115608k buffers
Swap: 979956k total, 17980k used, 961976k free, 58608k cached
total used free shared buffers cached
Mem: 505468 497452 8016 0 115608 58608
-/+ buffers/cache: 323236 182232
Swap: 979956 17980 961976
My system has 182232 kB free, not just 8016 kB. The extra free memory is
used by the system for improving access to the hardware rather than
being wasted. 8016 kB are being wasted right now.

In short: look at the second line at the output of 'free', or do the
math yourself.

--
Tzafrir Cohen
icq#16849755 jabber:tzafrir.cohen at xorcom.com
+972-50-7952406 mailto:tzafrir.cohen at xorcom.com
http://www.xorcom.com iax:guest at local.xorcom.com/tzafrir

tzafrir.cohen at xorco...
Guest

Posted: Fri Apr 25, 2008 8:10 am Post subject: [asterisk-users] noisy analog lines

One other thing,

On Fri, Apr 25, 2008 at 10:06:08AM +0200, Ian wrote:

Quote:

You bumped both txgain and rxgain. txgain is for audio Asterisk
transmits to the device (the telephone line, in this case). rxgain is
for audio recieves from the device.

I suspect you don't really need both . And a value of 10 might actually
influence the echo canceller. Try removing the two and see how things
work. Generally this value (like most values) is applied on a reload
(with asterisk 1.6 you can even use 'zap set {hw|sw}gain') . Generally
remove all of those txgain and rxgain limes from your zapata.conf, and
leave potentially just one near the top of the [channels] section - it
will effect all of them.

Use 'reload' or 'module reload chan_zap.so' to apply your changes and
ignore the scary messages about the "signalling" being ignored.

--
Tzafrir Cohen
icq#16849755 jabber:tzafrir.cohen at xorcom.com
+972-50-7952406 mailto:tzafrir.cohen at xorcom.com
http://www.xorcom.com iax:guest at local.xorcom.com/tzafrir

Guest

Posted: Mon Apr 28, 2008 2:37 pm Post subject: [asterisk-users] noisy analog lines

To help you adjust your rxgain and txgain appropriately, you can ask
your telco for the phone number for a "milliwatt test line". 10 is a
pretty high number for the gain, although it DOES depend on your
distance from the telco and the line quality. My rxgain ranges between
2.375 and 2.945 depending on the specific channel. I'm a half mile from
the center.

Ian wrote:

Quote:

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