[Asterisk-Users] PRI and echocancel

[mattf]

Hello,

I have a crossover PRI(Asterisk server to PBX) and a regular telco PRI T1
line and currently have echocancel=yes and echocancelwhenbridged=yes on
those spans in zapata.conf. I was discussing CPU load with another Asterisk
user and he mentioned that PRIs don't need echo cancelation and that turning
it off will reduced CPU load on the server. I checked many sample configs
and the archives and noticed that half of the people have echocancel on for
PRIs and half do not. I checked the Digium site and indeed in the FAQ they
say: "There should also be no echo on PRI connections". 

Does it really matter that much in terms of CPU usage and will it hurt at
all if I turn it off for the crossover PBX connection or the telco PRI that
I have? 

Thanks,

MATT---