Cisco SPA962-NA Administration Guide - Page 22

Feature Descriptions Chapter 1 Introducing Linksys 900 Series IP Phones Other Features Table 1-4 summarizes the features provided by SPA900 Series IP Phones. Table 1-4 Linksys ATA Features Feature Music On Hold Secure Calls Adjustable Audio Frames Per Packet DTMF Call Progress Tone Generation Call Progress Tone Pass Through Jitter Buffer-Dynamic (Adaptive) Description On a connected call, SPA900 Series 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. 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 *) SPA900 Series 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. SPA900 Series IP phones have 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. SPA900 Series IP phones can buffer incoming voice packets to minimize 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. SPA900 Series IP phones have a Network Jitter Level control setting for each line of service. The jitter level decides how aggressively SPA900 Series 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 900 Series IP Phone Administrator Guide 1-8 Document Version 3.0