Cisco SPA1001 Administration Guide - Page 22

Feature Descriptions Chapter 1 Introducing Linksys Analog Telephone Adapters 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 International Caller ID Delivery Secure Calls Adjustable Audio Frames Per Packet DTMF Call Progress Tone Generation Call Progress Tone Pass Through Full Duplex Audio Echo Cancellation-Up to 8 ms Echo Tail Description 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. 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. 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. 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. 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. This feature allows the user to hear the call progress tones (such as ringing) that are generated from the far-end network. 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. 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