asterisk users - Apr 2008 - Problems with Unicall and TE122B

Hi

By the past 2 months i have install a server with Asterisk with a E1 in 
Axtel(Mexico).     The call presented a Echo in
randoms call,  inside and outside.    I decide migrate for the last 
version Asterisk 18.1,Zaptel 1.49 and Unicall and instalaled
a new Digim Card TE122 B (Echo cancelation).   The echo goes away.   But 
i stat gaving probelms with  my incoming audio
 stream gets clipped / dropped when they speak.

I dont know if i need to move a parameter in unicall.conf, or in another 
file.

Thanks

Ruben