asterisk users - Nov 2009 - Dahdi channels interference

Hi friends,

I want opinions to resolve a problem about interferences with Dahdi
Channels.

I have rooms with many users in each one, when I try to spy this
channels all conferencist listen a noise like a "cavern" or
"tunnel" and
all rooms are mixed, people listen people of anothers rooms.

I'm using asterisk 1.4.26, channels are dahdi, and I'm using next
context:

exten => s,n,Chanspy(${CANAL},qoXv(-4))  -> this line permit to one
person (administrator) spy the rooms, when it happend this problem is
present...

I don understand what happend, is a problem about Dahdi channels? is a
problem about Chanspy? is a problem about asterisk version?  is a
problem about phone?

Thanks for yours comments and help.


-- 
Saludos cordiales,


Ing. Diana L?pez
PaloSanto Solutions
Departamento de Desarrollo
PaloSanto Solutions
Tel?fono: +5934-229-4440
Guayaquil - Ecuador