Distinctive Ring; Echo Cancellation - Nortel Remote Office 9110 Release Note

Standard 1.1

Distinctive ring

Remote Office does not support Distinctive ring functionality of any kind.

Echo cancellation

Due to the network delay introduced by the IP network, echo is more noticeable
in VoIP networks than traditional networks. All echo cancellation algorithms
need a small amount of time to adjust if the echo path changes. This results in
the initial syllable, or word, of the first sentence having echo. After that,
however, no echo is apparent.
This is a normal characteristic of the transition point between the VoIP network
and traditional analog facilities. If echo is not cancelled after the beginning of
the first sentence, a more serious problem (such as impedance mismatch) may be
present. Also note that some environments, such as conference calls, may
change the echo path. This also results in an adjustment period for Echo
Cancellation.
Note: After investigation, Global Network Technical Support (GNTS)
discovered that the source of echo on the majority of installations is incorrectly
configured analog trunks. Please ensure that the trunks are configured correctly
in the areas of trunk card type (EXUT/XUT), TIMP, and BIMP settings, and
jumper settings on the actual trunk card itself. Also, measure the line loss and
compensate using the trunk class of service NTC or TRC as required.
Nortel Networks recommends that the trunk card be an enhanced version
(EXUT). An EXUT supports more complex impedance situations. Please refer
to NTP 553-3001-106 for trunk cards and the NTP for your specific PBX for
more information. Also, if you are connecting recording equipment or Recorded
Announcement (RAN) devices to an analog trunk, ensure that the trunk
impedance matches the equipment impedance to ensure that echo does not
occur.
44 1.4.2 Release Notes for Remote Office and RLC