[Asterisk-Users] Still unacceptable echo on X101P

[Michael Graves]

On Mon, 30 Aug 2004 16:21:04 +0100, Kevin Walsh wrote:

>Rich Adamson [radamson at routers.com] wrote:
>> > 3. If impendance mismatch is the (or a major contributing) factor, can
>> > we not devise some interface circuit which will allow a variable rate
>> > on the impedance so we can "dial out" the echo based on individual line
>> > conditions?
>> >
>> That would be called the TDM card. It has a chipset that was designed
>> to match telco standards in many (if not all) countries. In Canada,
>> if you have x100p echo problems, you'll have them with the tdm card
>> as well.
>> 
>> You'll find plenty of discussion in the archives relative to x100p/tdm
>> echo problems unrelated to impedence mismatches. Seems there is an issue
>> with interrupt latency, pci controller, or something like that associated
>> with some motherboards that "is" impacting echo (as well as other things).
>> 
>> Multiple individuals have found that replacing their motherboards fixed
>> the echo problem with these cards, but no one (as yet) as put their
>> finger on why with any degree of accuracy. Lots of opinions, but no
>> real facts to date.
>> 
>> [snip]
>> 
>> There is a high probability (but this is a wild guess) the echo issue
>> has something to do with the specific chipset used by the motherboard
>> manufacturer, and if that guess is correct, probably something to do
>> with how interrupts are handled or pci controller issues, etc.
>> Something on certain motherboards seem to be delaying the transfer of
>> data to/from x100p/tdm cards, and that delay is sufficient enough to
>> fall outside the limits of the echo cancellation software within *.
>> 
>You could go to a lot of time, effort and expense buying a TDM card,
>fitting a new motherboard (PCI 2.2), fiddling with gains and trying
>all of the other suggestions that have been posted, or you could just
>buy an external FXO device, such as a Sipura SPA-3000, and expect it
>to just work.
>
>External devices are not sensitive to PCI latency and are not
>concerned with the brand of motherboard you use.  All facilities,
>such as echo cancellation, are provided onboard rather than via a
>software driver.
>
>I don't have echo problems on my X100P (at home) but that won't stop
>me from dumping it in favour of a Sipura SPA-3000 next month, once it
>gets full UK support in firmware (caller ID etc.).
>

Bear in mind that many of us who have been using the SPA-3000 in the US
have also been experiencing echo related problems. I'm trying the
latest firmware which is only a few days old, but I'm pretty close to
chucking it in favor of something else.

Michael

--
Michael Graves                           mgraves at pixelpower.com
Sr. Product Specialist                          www.pixelpower.com
Pixel Power Inc.                                 mgraves at mstvp.com

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