Polycom 1725-11530-200 Rev A1 manual Dtmf Tone Generation, Dtmf Event RTP Payload

Administrator’s Guide - SoundPoint® IP / SoundStation® IP Features

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.

Central	Configuration file:	Set the DTMF tone levels, autodialing on and off times, and
	sip.cfg	other parameters.
(boot
		• For more information, refer to 4.6.1.5.1 Dual Tone
server)
		Multi-Frequency <DTMF/> on page 99.
	Web Server	None.
Local	(if enabled)
	Local Phone User	None.
	Interface

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.

Central	Configuration file:	Enable or disable RFC 2833 support in SDP offers and spec-
	sip.cfg	ify the payload value to use in SDP offers.
(boot
		• For more information, refer to 4.6.1.5.1 Dual Tone
server)
		Multi-Frequency <DTMF/> on page 99.
	Web Server	None.
Local	(if enabled)
	Local Phone User	None.
	Interface

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.

58 Copyright © 2006 Polycom, Inc.