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<TITLE>RE: [Asterisk-Users] Echo - UK Impedance problem with X100P?</TITLE>
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<P><FONT SIZE=2>I am not willing to spend money on a system where even the most basic things are incompatible with everybody but the US, this is just stupid I am using the X100P in a small office so that we can have a small PBX, seems daft having to upgrade my hardware just because of another US oversight. I am using a Gigabyte Titan 4 Pro motherboard and also tried it on another PC with an Intel motherboard and it had the same affect it could be Zapata.conf but pin pointing this is getting stupid I might invest in a commercial PBX as this is wasting so much of my time, its a good idea but saying the product is in its infancy is an overstatement.</FONT></P>
<P><FONT SIZE=2>-----Original Message-----</FONT>
<BR><FONT SIZE=2>From: Rich Adamson [<A HREF="mailto:radamson@routers.com">mailto:radamson@routers.com</A>]</FONT>
<BR><FONT SIZE=2>Sent: 12 November 2004 13:27</FONT>
<BR><FONT SIZE=2>To: Asterisk Users Mailing List - Non-Commercial Discussion</FONT>
<BR><FONT SIZE=2>Subject: Re: [Asterisk-Users] Echo - UK Impedance problem with X100P?</FONT>
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<P><FONT SIZE=2>> I have an X100p interface (clone). The system works fine but I get</FONT>
<BR><FONT SIZE=2>> echo to a level where the system is all but unusable for IP PSTN. I</FONT>
<BR><FONT SIZE=2>> seem to remember reading somewhere that the UK line impedance is </FONT>
<BR><FONT SIZE=2>> different from the default compile and needs changing. I have</FONT>
<BR><FONT SIZE=2>> Wikied etc, but found nothing yet.</FONT>
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<P><FONT SIZE=2>The x100p (and presumably the clones) have an integrated circuit on the</FONT>
<BR><FONT SIZE=2>board that was manufactured for use in the US with 600 ohm pstn lines.</FONT>
<BR><FONT SIZE=2>The chip cannot be changed to any other impedance. However, there can</FONT>
<BR><FONT SIZE=2>be many different sources for the echo and impedance matching is only</FONT>
<BR><FONT SIZE=2>one of them. Others include:</FONT>
<BR><FONT SIZE=2> - incorrect * zapata.conf parameters</FONT>
<BR><FONT SIZE=2> - poorly engineered motherboards (eg, poor PCI bus, interrupt latency)</FONT>
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<P><FONT SIZE=2>For zapata.conf, try something like:</FONT>
<BR><FONT SIZE=2>echocancel=yes</FONT>
<BR><FONT SIZE=2>echotraining=800</FONT>
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<P><FONT SIZE=2>For poorly designed motherboards, there is no consolidated list of</FONT>
<BR><FONT SIZE=2>which ones are good/bad so you're left with trying another one on your</FONT>
<BR><FONT SIZE=2>own to see if it impacts the echo.</FONT>
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<P><FONT SIZE=2>The TDM04B digium card (as an example) does not use that same pstn</FONT>
<BR><FONT SIZE=2>chip, but rather another one from the same chip manufacturer. That</FONT>
<BR><FONT SIZE=2>chip does have support for something like 18 different "country"</FONT>
<BR><FONT SIZE=2>telco standards.</FONT>
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