Command Reference Guide

146 ● echo-canceller 3Com Router 5000 Family and Router 6000 Family
Command Reference
echo-canceller
Purpose Use the echo-canceller command to configure echo-cancellation parameters.
Use the
undo echo-canceller command to remove the configuration.
Syntax echo-canceller { enable | tail-length milliseconds | parameter {
convergence-rate value | max-amplitude value | mix-proportion-ratio
value | talk-threshold value } }
undo echo-canceller { enable | tail-length | parameter }
Parameters enable
Enables echo-cancellation function. By default, the
function is enabled.
tail-length milliseconds
Adjusts echo-cancellation duration, that is, the time
that elapse when a subscriber hears the voice echoed
back. It ranges from 0 to 64 ms and defaults to 32 ms.
parameter
sets echo-cancellation parameters.
convergence-rate value
Sets the ascending rate of comfort noise amplitude. It
ranges from 1 to 10 and defaults to 0. The greater the
value, the quicker the convergence. If a subscriber
hears echoes after speaking, or the background noise
of the peer is loud, you can increase this value. Note
that if this value is too great, the noise may be not
smooth enough.
max-amplitude value
Sets maximum amplitude of comfort noise. It ranges
from 0 to 2,048 and defaults to 256. The higher the
value, the greater the maximum noise amplitude. A
value of 0 indicates that the system performs only
nonlinear process and does not add comfort noise.
When the environmental noise is louder, you can
increase this value. Note that if this value is too great,
the noise may be not smooth enough.
mix-proportion-ratio value
Sets comfort noise mixture proportion control factor. It
ranges from 1 to 3,000 and defaults to 100. The
greater the value, the higher the proportion of noise in
the hybrid of noise and voice. If echoes occur when
only one subscriber is speaking, you can increase this
value. Note that if this value is too great, the voice may
be desultory.
talk-threshold value
Sets the threshold of simultaneous talks. It ranges from
1 to 2 and defaults to 1. If echoes occur when the two
parties speak simultaneously, you may increase this
value. Note that if this value is too great, the filter
factor convergence rate may become slow.
Example Set the echo-cancel sampling time as 24 ms on subscriber line 1/0/0.