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Chapter 1
Introducing Linksys Analog Telephone Adapters
Feature Descriptions
The Linksys ATA has a Network Jitter Level control setting for each line of service. The jitter level
decides how aggressively the Linksys ATA tries 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.
Other Features
The following table summarizes other features provided by Linksys ATAs.
Table 1-4
Linksys ATA Features
Feature
Description
International Caller ID
Delivery
In addition to support of the Bellcore (FSK) and Swedish/Danish (DTMF)
methods of Caller ID (CID) delivery, release 2.0 adds a large subset of
ETSI-compliant methods to support international CID equipment.
Different types of CID delivery method can be obtained by
mixing-and-matching some of the steps as shown.
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
Frames Per Packet
This feature allows the user to set the number of audio frames contained in
one 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 *) The Linksys ATA
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
Generation
The Linksys ATA has configurable call progress tones. Parameters for each
type of tone may include number of frequency components, frequency and
amplitude of each component, and cadence information.
Call Progress Tone
Pass Through
This feature allows the user to hear the call progress tones (such as ringing)
that are generated from the far-end network.
Full Duplex Audio
Full-duplex is the ability to communicate in two directions simultaneously
so that more than one person can speak at a time. Half-duplex means that
only one person can talk at a time, like a CB radio or walkie-talkie, which
is unnatural in normal free-flowing two-way communications. The Linksys
ATA supports full-duplex audio.
Echo
Cancellation—Up to 8
ms Echo Tail
The SPA3102 supports hybrid line echo cancellation. This feature uses the
G.165 echo canceller to eliminate up to 8 ms of line echo. This feature does
not provide acoustic echo cancellation on endpoint devices; that is, an end
user speakerphone.
Linksys ATA Administrator Guide
1-8
Document Version 3.1