Linksys SPA 900 SERIES manual Other Features, Feature Description, Dtmf

Chapter 1 Introducing Linksys IP Phones

Feature Descriptions

Other Features

Table 1-4summarizes the features provided by Linksys IP Phones.

Table 1-4 Linksys Phone Features

Feature	Description
Music On Hold	On a connected call, Linksys IP phones may place the remote party on call.
	If the remote party indicates that they can still receive audio while the call is
	holding, the MOH server sends streaming audio.
Secure Calls	A user (if enabled by service provider or administrator) has the option to
	make an outbound call secure in the sense that the audio packets in both
	directions are encrypted.
Adjustable Audio	This feature allows you to set the number of audio frames contained in one
Frames Per Packet	RTP packet. Packets can be adjusted to contain from 1–10 audio frames.
	Increasing the number of packets decreases the bandwidth utilized, but it
	also increases delay and may affect voice quality.
DTMF	In-Band and Out-of-Band (RFC 2833) (SIP INFO) Linksys IP phones may
	relay DTMF digits as out-of-band events to preserve the fidelity of the digits.
	This can enhance the reliability of DTMF transmission required by many
	IVR applications such as dial-up banking and airline information.
Call Progress Tone	Linksys IP phones have configurable call progress tones. Parameters for
Generation	each type of tone may include number of frequency components, frequency
	and amplitude of each component, and cadence information.
Call Progress Tone Pass	This feature allows you to hear the call progress tones (such as ringing) that
Through	are generated from the far-end network.
Jitter Buffer—Dynamic	Linksys IP phones can buffer incoming voice packets to minimize
(Adaptive)	out-of-order packet arrival. This process is known as jitter buffering. The
	jitter buffer size proactively adjusts or adapts in size, depending on changing
	network conditions.
	Linksys IP phones have a Network Jitter Level control setting for each line
	of service. The jitter level decides how aggressively Linksys IP phones try
	to shrink the jitter buffer over time to achieve a lower overall delay. If the
	jitter level is higher, it shrinks more gradually. If jitter level is lower, it
	shrinks more quickly.

	Linksys IP Phone Administrator Guide
Firmware Version 5.1		1-7