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Administrator’s Guide - SoundPoint
®
IP / SoundStation
®
IP Features
58 Copyright © 2006 Polycom, Inc.
3.3.4 DTMF Tone Generation
The phone generates dual tone multi-frequency (DTMF) tones in response to user dial-
ing 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 deci-
sion is based on the capabilities of the remote end point.
3.3.5 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 tech-
nique 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.
3.3.6 Acoustic Echo Cancellation (AEC)
The phone employs advanced acoustic echo cancellation for hands-free operation.
Both linear and non-linear techniques are employed to aggressively reduce echo yet
provide for natural full-duplex communication patterns.
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 4.6.1.5.1 Dual Tone
Multi-Frequency <DTMF/> on page 99.
Local
Web Server
(if enabled)
None.
Local Phone User
Interface
None.
Central
(boot
server)
Configuration file:
sip.cfg
Enable or disable RFC 2833 support in SDP offers and spec-
ify the payload value to use in SDP offers.
• For more information, refer to 4.6.1.5.1 Dual Tone
Multi-Frequency <DTMF/> on page 99.
Local
Web Server
(if enabled)
None.
Local Phone User
Interface
None.