Re: [Asterisk-Users] echo / delay problem

2005-03-22 Thread Barry FAWTHROP
I'm in the US, using cards bought direct from Digium.
I have lowered the rxgain and txgain to -8 and that seems to be helping 
futher.
I wish I could understand why?

The problem with more time is that I can hear myself in the headset of the 
std. phone
as well as the party on the other end.  The other person just hears me.

The problem then is somewhere internal. as I can talk into the mouthpiece 
and
hear myself in the speaker???

Thanks
Barry
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RE: [Asterisk-Users] echo / delay problem

2005-03-22 Thread Kris Boutilier
 -Original Message-
 From: Barry FAWTHROP [mailto:[EMAIL PROTECTED]
 Sent: Tuesday, March 22, 2005 7:12 AM
 To: asterisk-users@lists.digium.com
 Subject: Re: [Asterisk-Users] echo / delay problem
 
 
 I'm in the US, using cards bought direct from Digium.
 I have lowered the rxgain and txgain to -8 and that seems to 
 be helping futher.
 I wish I could understand why?

Consider the following bad ASCII diagram of the amplitude of the signal as it 
travels from your handset to the remote end, becomes an echo and comes back to 
your handset:

1.00| 
| |
0.75|   | (effect of txgain -8.0)
| |
0.50|--^-   
|  |
0.25|  | (effect of rxgain -8.0)
|  |
0.00|   
|-
|||||
||||\Echo level arriving at local handset
|||\Echo level arriving from remote end
||| Signal level arriving at remote end
| \-Signal level leaving to the PSTN 
\-Signal level leaving local handset


Now consider the amplitude of the legitimate speech originating at the remote 
end:

1.00| -
|  |
0.75|| (effect of rxgain -8.0)
|  |
0.50|   
|  
0.25|  
|  
0.00|   
|--
||
|  \Echo level arriving at handset
\-Signal level leaving remote handset

It follows then that a signal that is attenuated going out and then further 
attenuated coming back in to your system (ie. the echo) will be relatively 
quieter than a signal that is just attenuated once (ie. the remote end 
conversation). Remember that a gain expressed in Db is a logarithmic measure so 
two passes are more than double the attenuation. 

This is known as a 'loss plan' in telco spheres and was traditionally used in 
analog systems to make echo (and sideton) more managable. Theres some 
interesting blurb on loss planning at: http://telecom.tbi.net/lossplan.htm  or 
consult Google.

It's also important to understand that the training algorithms in many echo 
cancellers rely on being able to differentiate between the echo and legitimate 
far end signal and one of the mechanisms used is to measure the average 
relative signal levels. Thus an outgoing signal that is too 'hot' (ie. has 
excessive amplitude) may not be properly echo-supressed as the signal cannot be 
differentiated from the far end signal, thus getting your gains correct is an 
important part of PSTN interfacing.

Hope that helps.

Kris Boutilier
Information Services Coordinator
Sunshine Coast Regional District
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Re: [Asterisk-Users] echo / delay problem

2005-03-19 Thread Rich Adamson
 I'm having with an echo or delay
 
 I connect to the PSTN with a x100p  and then connect a std. phone
 to a FXS module on a TDM10B.
 
 The std phone is only 2-wire so I know this is not helping.
 (yes I have read the 2-wire 4-wire issue)
 
 I have tried many echocancel values. The best thing to help was
 rxgain and txgain. below is my current zapata.conf file
 
 All help would be grateful. I have tried and tried for 2 weeks
 it is rather annoying and irating to hear this delay/echo
 
 I would call it a delay since you can hear the end of the sentence repeat 
 over
 and over. Also every now and again  it sounds like a underwater submarine
 with ping and all.
 
 
 Thanks in advance
 Barry
 
 
 
 [channels]
 echocancel= 16
 echocancelwhenbridged = yes
 echotraining  = no  ;; yes
 rxgain= -2.0
 txgain= -2.0

If you are in the US and using a digium x100p, then try the following:
 echotraining=800
 echocancel=yes
(The values you are showing above aren't even valid parameters.)

If you are outside the US, there isn't much you can do since the x100p
card was specifically designed to operate with US 600 ohm impedance
pstn lines.

If you have a x100p clone, it is likely the problem. Replace it with
something capable of matching the pstn impedance for whatever country
you are located in.


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Re: [Asterisk-Users] echo / delay problem

2005-03-19 Thread Mikael Magnusson
On Sat, Mar 19, 2005 at 07:19:39AM -0600, Rich Adamson wrote:
 
 If you are outside the US, there isn't much you can do since the x100p
 card was specifically designed to operate with US 600 ohm impedance
 pstn lines.
 
 If you have a x100p clone, it is likely the problem. Replace it with
 something capable of matching the pstn impedance for whatever country
 you are located in.
 

Loading wcfxo with option opermode=1 should select CTR21 mode, which
according to wcfxo.c (in zaptel) should be used in Austria, Belgium,
Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy,
Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland,
and UK. The default is to use FCC mode, which is used in the US.

Regards,
Mikael Magnusson

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Re: [Asterisk-Users] echo / delay problem

2005-03-19 Thread Rich Adamson

  If you are outside the US, there isn't much you can do since the x100p
  card was specifically designed to operate with US 600 ohm impedance
  pstn lines.
  
  If you have a x100p clone, it is likely the problem. Replace it with
  something capable of matching the pstn impedance for whatever country
  you are located in.
  
 
 Loading wcfxo with option opermode=1 should select CTR21 mode, which
 according to wcfxo.c (in zaptel) should be used in Austria, Belgium,
 Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy,
 Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland,
 and UK. The default is to use FCC mode, which is used in the US.

The x100p does not have a programable chipset for impedance matching.
That parameter was intended for the TDM card.


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Re: [Asterisk-Users] echo / delay problem

2005-03-19 Thread Mikael Magnusson
On Sat, Mar 19, 2005 at 09:22:22AM -0600, Rich Adamson wrote:
 
   If you are outside the US, there isn't much you can do since the x100p
   card was specifically designed to operate with US 600 ohm impedance
   pstn lines.
   
   If you have a x100p clone, it is likely the problem. Replace it with
   something capable of matching the pstn impedance for whatever country
   you are located in.
   
  
  Loading wcfxo with option opermode=1 should select CTR21 mode, which
  according to wcfxo.c (in zaptel) should be used in Austria, Belgium,
  Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy,
  Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland,
  and UK. The default is to use FCC mode, which is used in the US.
 
 The x100p does not have a programable chipset for impedance matching.
 That parameter was intended for the TDM card.


Ok, maybe it isn't programmable, but there seems to be two different
DAA's used in the clones[1]. Si3012 for the US market and Si3014 for the
global market. I assume this has to do with the line interface. I
bought a clone in Sweden that has the Si3014. It should support the line
impedance used in Sweden I think, since it's marked with the following label:

  Clas Ohlson AB
  Modell/Malli: AMI-IE92 Art.nr/nro:32-2055
  CE
  For use in Sweden, Norway and Finland.
  To be connected to the public switched telefone network.
  Hereby, Clas Ohlson, declares that this modem is in
  complience with the essential requirements and other
  relevant provisions of Directive 1999/5/EC.

[1]http://www.intel.com/design/modems/linecard.htm

Regards
Mikael Magnusson

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Re: [Asterisk-Users] echo / delay problem

2005-03-19 Thread Rich Adamson
If you are outside the US, there isn't much you can do since the x100p
card was specifically designed to operate with US 600 ohm impedance
pstn lines.

If you have a x100p clone, it is likely the problem. Replace it with
something capable of matching the pstn impedance for whatever country
you are located in.

   
   Loading wcfxo with option opermode=1 should select CTR21 mode, which
   according to wcfxo.c (in zaptel) should be used in Austria, Belgium,
   Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy,
   Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland,
   and UK. The default is to use FCC mode, which is used in the US.
  
  The x100p does not have a programable chipset for impedance matching.
  That parameter was intended for the TDM card.
 
 
 Ok, maybe it isn't programmable, but there seems to be two different
 DAA's used in the clones[1]. Si3012 for the US market and Si3014 for the
 global market. I assume this has to do with the line interface. I
 bought a clone in Sweden that has the Si3014. It should support the line
 impedance used in Sweden I think, since it's marked with the following label:
 
   Clas Ohlson AB
   Modell/Malli: AMI-IE92 Art.nr/nro:32-2055
   CE
   For use in Sweden, Norway and Finland.
   To be connected to the public switched telefone network.
   Hereby, Clas Ohlson, declares that this modem is in
   complience with the essential requirements and other
   relevant provisions of Directive 1999/5/EC.
 
 [1]http://www.intel.com/design/modems/linecard.htm

So, does that apply to the OP (I think he posted from Germany, but
I could be wrong)?


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Re: [Asterisk-Users] echo / delay problem

2005-03-19 Thread C F
  [channels]
  echocancel= 16
  echocancelwhenbridged = yes
  echotraining  = no  ;; yes
  rxgain= -2.0
  txgain= -2.0
 
 If you are in the US and using a digium x100p, then try the following:
  echotraining=800
  echocancel=yes
 (The values you are showing above aren't even valid parameters.)

Why not? I don't see what wrong with those values? Can you explain please?
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[Asterisk-Users] echo / delay problem

2005-03-18 Thread Barry FAWTHROP
I'm having with an echo or delay
I connect to the PSTN with a x100p  and then connect a std. phone
to a FXS module on a TDM10B.
The std phone is only 2-wire so I know this is not helping.
(yes I have read the 2-wire 4-wire issue)
I have tried many echocancel values. The best thing to help was
rxgain and txgain. below is my current zapata.conf file
All help would be grateful. I have tried and tried for 2 weeks
it is rather annoying and irating to hear this delay/echo
I would call it a delay since you can hear the end of the sentence repeat 
over
and over. Also every now and again  it sounds like a underwater submarine
with ping and all.

Thanks in advance
Barry

[channels]
language  = en
context   = inbound
signalling= fxs_ks
usecallerid   = yes
hidecallerid  = no
callwaiting   = yes
usecallingpres= yes
callwaitingcallerid   = yes
threewaycalling   = yes
echocancel= 16
echocancelwhenbridged = yes
echotraining  = no  ;; yes
rxgain= -2.0
txgain= -2.0
musiconhold   = default
channel = 1
context   = intern
signalling= fxo_ks
callwaiting   = yes
usecallerid   = yes
echotraining  = no ;; yes
echocancel= 16
channel = 2
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