[Asterisk-Users] Echo - UK Impedance problem with X100P?

[Rich Adamson]

> > The x100p (and presumably the clones) have an integrated circuit on
> > the board that was manufactured for use in the US with 600 ohm pstn
> > lines. The chip cannot be changed to any other impedance. However,
> > there can be many different sources for the echo and impedance
> > matching is only one of them. Others include:
> >  - incorrect * zapata.conf parameters
> >  - poorly engineered motherboards (eg, poor PCI bus, interrupt
> > latency)
> >
> 
> [snip]
> 
> There are two types of alternative cards (not starting a discussion on who
> made it first!), one called AMI-IA92 (Si3021/Si3012/MD3200) with a FCC
> approval and one called AMI-IE92 (Si3021/Si3014/MD3200) with a R&TTE
> approval.
> 
> The AMI-IE92 have additional components on board for setting AC real/complex
> termination as well as DC termination (Japan Mode/FCC Mode/CTR21 Mode).
> 
> Both card types are compatible but the wcfxo driver does not utilise the
> additional settings on the AMI-IE92 card.
> 
> Source:
> Chipsets (login required)
> 
https://www.mysilabs.com/public/documents/tpub_doc/dsheet/Wireline/Silicon_DAA/en/si3034.pdf

> 
https://www.mysilabs.com/public/documents/tpub_doc/dsheet/Wireline/Silicon_DAA/en/si3035.pdf

> 
> Amigo Communications product sheet (www.amigocom.com)
> http://61.31.72.100/amigocom/products/ami_ia92_ie92.htm
> 

For those that would like to play around with the above, might take
a look at zaptel/fxstest.c (and the associated Makefile complile
options) as it can be used to modify/view the tdm04b chip parameters.
I'm not a programmer, but doubt whether it would take much to
modify it to exercise the cards noted above.