3Com NBX 100 Administrator's Manual page 261

Table 36 System Settings Audio Settings Dialog Box Fields (continued)
Field Purpose
System-wide Audio Select one of these compressions settings as the default
Compression setting for all calls:
None - G711 — No compression, G.711 (MULAW) audio
encoding
Med - ADPCM — Medium compression, ADPCM audio
encoding
High - G729 — High compression, G.729 audio encoding.
You can override the system wide setting for individual
telephones, line card ports or T1/E1 spans (3C10116D and
3C10165D only).
Audio Compression Select one of these compressions settings as the default
on VTL Calls setting for calls over virtual tie lines:
None - G711 — No compression, G.711 (MULAW) audio
encoding
Med - ADPCM — Medium compression, ADPCM audio
encoding
High - G729 — High compression, G.729 audio encoding.
Echo Troubleshooting controls can reduce or eliminate audio feedback (echo)
during conversations. The NBX system has default mechanisms to deal with echo,
however, extreme conditions can induce echo that is beyond the scope of the
default mechanisms.
NOTE: When additional echo suppression is enabled for analog and digital line
cards, echo should be reduced or eliminated. However, in rare conditions, the
additional echo suppression may cause incoming audio to occasionally fade in and
out.
NBX Handset Enables additional echo suppression on calls between internal
Acoustic Echo extensions. Acoustic echo typically occurs when the phone
Suppression volume is set to maximum and audio feeds back from the ear
piece to the mouthpiece.
Analog Line Cards Enables echo suppression on calls between internal extensions
Echo Suppression and outside callers.
Digital Line Cards Enables echo suppression on calls that use digital line
Echo Suppression connections.
System Settings 261