Nortel Networks 9150 - Manual (Page 205)

Remote Gateway 9150 Installation and Administration Guide 175
January 2005 Configuring the Remote Gateway 9150 unit
NLP
The Non-Linear Processor (NLP) works with the Remote Gateway 9100 Series
echo canceller to reduce echo. Echo occurs in a telephone call when the
transmitted signal reflects and is received by the transmitting device. To cancel
the echo, the Remote Gateway 9100 Series system monitors the audio stream
looking for echo. When echo is identified it is digitally (mathematically)
removed. If the echo is very strong, a small amount of echo may remain called
“residual” echo. The aggressiveness of the NLP determines how quickly and
how effectively the Remote Gateway 9100 Series NLP reduces the residual
echo.
The operation of the NLP can affect how the audio sounds during double-talk
situations - when both parties are speaking. Cultural differences also change
how often double-talk occurs during a conversation.
Nortel recommends the following settings as a starting point:
!
RLC: NLP Enabled - Less Aggressive (default)
!
9150: NLP Enabled - More Aggressive (default)
If the Remote Gateway 9150 unit user hears echo during conversations, adjust
the settings, as follows:
!
RLC: NLP Enabled - More Aggressive
!
9150: NLP Enabled - Less Aggressive
If the party on the PBX side hears echo during conversations, adjust the settings,
as follows:
!
RLC: NLP Enabled - More Aggressive
!
9150: NLP Enabled - More Aggressive
The NLP does not have to operate aggressively if echo is not present. If echo is
not present but double-talk is present, even with Less Aggressive settings, try
disabling the NLP on the RLC.
Upgrades
When you perform a Remote Gateway 9150 firmware upgrade from release
1.3.4 or earlier, NLP settings return to their default values.