DEFINITY Enterprise Communications Server Release 7
Maintenance for R7r
555-230-126 Issue 4
June 1999
Alarms, Errors, and Troubleshooting
5-65Multimedia Call Handling (MMCH)
5
2. Check the VC (TN788B) board using the test board xxyy long command.
3. Drop the call.
4. Find another available port, the n:
a. Busyout the port to which the end point was connec ted.
b. Make another call to the same c onference. If the problem c orrects
itself, then the previous port may b e bad. If there are other VC
boards with sufficient availab le ports to replace c alls on the current
VC, then pull the board that has the b ad endpoint on it (the status
conference command disp lays the encoder p ort associated with
the call). The system will automatically reestabli sh the VC
connections without drop ping the call. If this fixes the problem, then
replace the board, as it has at least one bad por t. Reseating the
board may temporarily fix the p roblem due to the hard reset don e to
the board.
Audio Echo
Echo in conference calls, particularly those with large delay characteristics, is
totally disruptive. When Voice Activated Switc hing is taken into accou nt, the
effects are disastrous. Various arrangements of the microp hone(s) and room
speaker(s) may be needed.
For some Lucent Technologies Vistium endpoints, if an external sp eaker is
attached or was attached when the system was last rebooted, this end point will
cause audio echo throug hout 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 loc ated too close to the sp eakers of an endpoint,
then acoustic echo is c reated. The microphone must b e 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 ech o canceller in the cod ec retrains itself, some will
require a manual reset. If a PictureTel keypad is configured with external
microphones connec ted to the keypad, then the internal microphone and
external microphone(s) “sin g” to each other if the “ ext mic” bat switch is set to
“int mic” on the b ack of the keypad. In this configuration, VAS locked on that site,
and the acoustic “ singing” was ina udible.
Rate Adaptation
Because of a lack of a cl ear explanation in standards, som etimes endpoints do
not work well with each other and the DEFINITY MMCH. The MMCH will only
allow a conference to downg rade from 64kbps to 5 6 kbps operation on
conferences that have the Rate Adaptation flag set to y.