Cisco SR520-FE-K9 Administration Manual page 91

Configuring Voice
Configuring Voice Services
Cisco SRP500 Series Services Ready Platforms Administration Guide (SRP520 Models)
Feature
Modem and Fax Pass-
Through
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
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 pass-
through 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
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.
6
Regional
156.
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