Cisco SRP521W-K9-G1 Administration Guide - Page 91

Configuring Voice Configuring Voice Services 6 Feature Modem and Fax PassThrough Adaptive Jitter Buffer Secure Calls Description • Modem pass-through mode can be triggered only by predialing the number set in the Modem Line Toggle Code. See Regional Page, page 136. • FAX pass-through mode is triggered by the detection of a CED/CNG tone or an NSE event. • Echo canceller is automatically disabled for Modem passthrough mode. • Echo canceller is disabled for FAX passthrough if the parameter FAX Disable ECAN (Line 1 or 2 tab) is set to "yes" for that line (in that case FAX pass-through is the same as Modem pass-through). • Call waiting and silence suppression is automatically disabled for both FAX and Modem pass-through. In addition, out-of-band DTMF transmission is disabled during modem or fax passthrough. The SRP can buffer incoming voice packets to minimize the impact of variable network delays. This process is known as jitter buffering. The size of the jitter buffer adapts reactively to suit changing network conditions. The SRP has a Network Jitter Level control setting for each line of service. The jitter level determines how aggressively the SRP 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. Adaptive Jitter Buffer is configured in the Line pages. See Line Pages (1-2), page 156. 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. Cisco SRP500 Series Services Ready Platforms Administration Guide (SRP520 Models) 91