[Asterisk-Users] where to buy x100p

Remco Barende asterisk at barendse.to
Sun Jan 30 10:43:18 MST 2005


wow! excellent information, this should be added to the wiki under x100p / 
tdm400.

Especially the info that the X100P is 600 ohm only would have made it a 
lot clearer to me that I needn't buy an X100P (clone) for use in Europe

On Sun, 30 Jan 2005, Rich Adamson wrote:

>> Why does the X100P have echo and the Wildcard TDM400P have no echo?
>>
>> I thought the only advantage of using the TDM400P was that it used
>> less interrupts than the X100P?
>>
>> Are there any other advantages?
>
> One of the major differences between the two cards is that tdm
> fxo modules have support for multiple country pstn interfaces where
> the x100p was designed for the 600 ohm US pstn standard only.
> Mismatches associated with a 600 ohm card and pstn interface is
> known to be a source of echo.
>
> The internal rtp data path in * for both the x100p and tdm card is
> basically the same path (and the same echo canceller).
>
> The interrupts for both cards is exactly the same; 1,000 interrupts
> per second. The interrupt rate is associated with the sampling of
> digitized voice (data), and is not a hardware-card dependent item
> in this case.
>
> The tdm card uses a Silcon Labs chipset that includes a two wire to
> four wire hybrid, which _should_ contribute to reducing fxo echo.
> However, the default driver does not currently preload (or dynamically)
> adjust the hybrid coefficients to optimize the pstn line interface.
> There has been some work going on recently to do that, but I don't
> believe the code is production ready as yet. Setting the coefficients
> is primarily a near-end echo optimization.
>
> The tdm card currently has another issue that causes at least some
> implementations to fail after several days/weeks of operation. There
> is some work going on at digium to identify the source of that problem,
> however with intermitant problems that only show up over long periods
> of time, it is very difficult to catch and identify the root cause.
> The failure requires asterisk to be stopped and the card drivers to
> be reloaded to correct the issue.
>
> Once the tdm issues have been resolved, its my opinion the card will
> be a very cost effective way to interface to pstn lines in the small
> office (and home) environment.
>
>
>
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