[asterisk-users] The High Performance Echo Canceller (HPEC)

[Nic Bellamy]

Wireless wrote:
> Does anyone know if the HPEC will work on a Sangoma A200 / 2 port FXO card?
> (I'm assuming so as it still uses Zapel)  I've 2 PSTN lines one of which I
> cannot get rid of the echo, I've tried a 2GHz machine as apposed to my
> normal P3 650MHz and this made no difference. Would the 650Mhz be enough to
> run HPEC on one line (I assume only needing one licence)
>   
It should work, providing all the Wanpipe stuff is ready to work with 
Zaptel 1.2.13.

As far as performance, you should be able to get one, maybe two channels 
of 1024 tap cancellation on the P3, but I'd advise careful testing, 
perhaps even using oprofile for a while to keep an eye on what's using what.

You also have to watch out extra carefully due to the following: HPEC 
works in "sparse" mode, meaning it can cover 1024 taps, but just cancels 
echo in the parts where there is echo - hence CPU usage will likely 
change quite a bit with different echo paths - ie. a simple single 
reflection path will use less CPU than a complicated path with more than 
one reflection.

Cheers,
    Nic.

-- 
Nic Bellamy,
Head Of Engineering, Vadacom Ltd - http://www.vadacom.co.nz/