3Com SuperStack II PathBuilder S330 Reference Manual page 139

Figure 116 VCM Channel Configuration Menu
3 Set the following channel configuration parameters:
Encoding — Encoding scheme: A-law (international) or Mu-law (United States).
Voice Coding — Voice compression algorithm: Clear data, 64kbps PCM, 40kbps
ADPCM, 32kbps ADPCM, 24kpbs ADPCM, 16kbps ADPCM, or 8kbps G.729A.
The Voice Coding setting must match that at the end of the circuit.
Silence Compression — Enable (On) or disable (Off) silence compression and
comfort noise injection. If you enable Silence Suppression, the system will
automatically insert comfort noise when it detects silence in the voice
transmission.
Echo Cancellation — Enable (On) or disable (Off) echo cancellation. If you enable
Echo Cancellation, the DSP will perform up to 16ms echo cancellation. For further
information about delay and when to use echo cancellation, see "Delay and Echo
Cancellation" later in this section.
DTMF Relay — Enable (On) or disable (Off) DTMF Relay. If you enable DTMF Relay
the Voice Compression module sends DTMF using a different packet. If you disable
DTMF Relay, the Voice Compression module simply compresses the voice signal.
Fax/Modem Support — Use this parameter to specify the voice compression
setting to which you want the signal to go when a fax or modem signal is
detected: 64kbps PCM or 40 kbps ADPCM. Fax and modem detection is always
enabled. When a fax or modem signal is detected, the voice signal is
decompressed. As soon as the fax or modem signal is gone, the signal reverts to
the Voice Coding setting you specified.
The Fax/Modem Support setting must match that at the end of the circuit.
4 Select [7] Apply Setting to Channel(s) to apply your settings to one or more
channels. The following prompt appears:
Enter Channel(s) (1-8):
5 Enter the number(s) of the channel(s) to which you want to apply the settings. You
can enter a single channel, a range of channels (for example:
channels separated by commas (for example:
Configuring the Voice Compression Module
).
4,5,6
125
), or a list of
4-6