Polycom SIP 3.0.2 ユーザーズマニュアル

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 Configuring Your System
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DTMF Tone Generation
The phone generates dual tone multi-frequency (DTMF) tones in response to 
user dialing on the dial pad. These tones are transmitted in the real-time 
transport protocol (RTP) streams of connected calls. The phone can encode the 
DTMF tones using the active voice codec or using RFC 2833 compatible 
encoding. The coding format decision is based on the capabilities of the remote 
end point.
Configuration changes can performed centrally at the boot server:
DTMF Event RTP Payload
The phone is compatible with RFC 2833 - RTP Payload for DTMF Digits, 
Telephony Tones, and Telephony Signals
. RFC 2833 describes a standard 
RTP-compatible technique for conveying DTMF dialing and other telephony 
events over an RTP media stream. The phone generates RFC 2833 (DTMF 
only) events but does not regenerate, nor otherwise use, DTMF events 
received from the remote end of the call.
Configuration changes can performed centrally at the boot server:
Acoustic Echo Cancellation
The phone employs advanced acoustic echo cancellation (AEC) for hands-free 
operation. Both linear and non-linear techniques are employed to aggressively 
reduce echo yet provide for natural full-duplex communication patterns.
When using the handset on any SoundPoint IP phones, AEC is not normally 
required. In certain situations, where echo is experienced by the far-end party, 
when the user is on the handset, AEC may be enabled to reduce/avoid this 
echo. To achieve this, make the following changes in the sip.cfg configuration 
file (default settings for these parameters are disabled):
voice.aec.hs.enable = 1
voice.aes.hs.enable = 1
voice.ns.hs.enable = 1
voice.ns.hs.signalAttn = -6
voice.ns.hs.silenceAttn = -9
Central 
(boot server)
Configuration file: 
sip.cfg
Set the DTMF tone levels, autodialing on and off times, and other 
parameters.
For more information, refer to 
 on page 
Central 
(boot server)
Configuration file: 
sip.cfg
Enable or disable RFC 2833 support in SDP offers and specify the 
payload value to use in SDP offers.
For more information, refer to 
 on page