Echo in T1 voice blade for 6500 switch

[gchui]

Dear all,

I use the T1 voice blade for the 6500 and I get a couple of seconds of echo on certain calls. Does any one know how to solve it? I saw from the forum, it is an expected behavior in T1 voice blade. Is there any release notes regarding about this? Thanks for your help

Gary

[s-doyle]

Echo is normally caused by a mismatch in impedance from the four-wire network switch conversion to

the two-wire local loop.

The follwoing Parameters has to be adjusted

echo-cancel enable

echo-cancel coverage

output attenuation

input gain

Also check the following link which has a sample Echo Analysis Case Study and to adjust the parameters accordingly to your topology

Echo Analysis for Voice over IP

http://www.cisco.com/univercd/cc/td/doc/cisintwk/intsolns/voipsol/ea_isd.htm#xtocid29