Avaya DEFINITY Server CSI Maintenance Manual page 159

Troubleshooting Multimedia Call Handling (MMCH)
Solution
If the audio is not muffled:
1. Use the status conference command to determine which port on the
TN788B (VC board) is connected to this endpoint.
2. Check the VC (TN788B) board using the test board xxyy long command.
3. Drop the call.
4. Find another available port, then:
a. Busyout the port to which the endpoint was connected.
b. Make another call to the same conference. If the problem corrects
Audio Echo
Echo in conference calls, particularly those with large delay characteristics, is
totally disruptive. When Voice Activated Switching is taken into account, the
effects are disastrous. Various arrangements of the microphone(s) and room
speaker(s) may be needed.
For some Vistium endpoints, if an external speaker is attached or was attached
when the system was last rebooted, this endpoint will cause audio echo
throughout the conference. First, isolate the offending endpoint by asking each
endpoint to mute, one at a time, until the echo disappears.
If the input from an endpoint is located too close to the speakers of an endpoint,
then acoustic echo is created. The microphone must be moved away from the
speakers.
Normally, if any microphone in the room is moved relative to the speakers, that
site will cause echo until the echo canceller in the codec retrains itself, some will
require a manual reset. If a PictureTel keypad is configured with external
microphones connected to the keypad, then the internal microphone and external
microphone(s) "sing" to each other if the "ext mic" bat switch is set to "int mic" on
the back of the keypad. In this configuration, VAS locked on that site, and the
acoustic "singing" was inaudible.
555-233-119
itself, then the previous port may be bad. If there are other VC
boards with sufficient available ports to replace calls on the current
VC, then pull the board that has the bad endpoint on it (status
conference displays the encoder port associated with the call). The
system will automatically reestablish the VC connections without
dropping the call. If this fixes the problem, then replace the board, as
it has at least one bad port. Reseating the board may temporarily fix
the problem due to the hard reset done to the board.
Issue 5 October 2002
159