Auerswald COMpact 4000 Operation Manual page 599

DTMF signalling
Requirements:
• Inband signalling: uncompressed codec (G.711)
Inband: The PBX uses the same channel to transfer the DTMF signals and the voice data
(DTMF tones).
Outband (RFC 2833): The PBX uses different channels to transfer the DTMF signals and the
voice data. The DTMF tones are filtered out of the voice data.
Both procedures: The PBX transmits the DTMF signals on two channels (1st contains DTMF
tones together with the voice data + 2nd contains the DTMF signal).
Echo Cancellation
.This compensates for local echoes and reverberation effects.
Jitter buffer (40 to 160)
The size of the jitter buffer specifies how many RTP packets can be cached, to buffer disrup-
tions or compensate for them.
Codec settings
Requirements:
• external VoIP channel that supports different codecs (optional, see Important Information >
Product Details > Basic Assembly and Extensions section)
• VoIP provider who supports the different codecs
The PBX makes various codecs available. The selection of a codec affects the quality of a VoIP
call. Different codecs can be configured, depending on the available connection bandwidth,
ranging from codecs with the best possible VoIP call quality down to codecs with high
compression (low bandwidth). The codec actually used for a call is not fixed until the codec is
negotiated with the VoIP provider.
Best available quality
Selects a codec sequence with best possible VoIP call quality (high bandwidth) as highest
priority.
Good compromise
Selects a compromise between VoIP call quality (high bandwidth) and compression (lower
bandwidth) for the codec sequence.
Best possible compression
Selects a codec sequence with stronger compression (lower bandwidth) as highest priority.
COMpact 4000 - Firmware V6.6A - Installation, Operation and Configuration V03 03/2016
Settings
VoIP
VoIP Provider Settings
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