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Cisco VISM Installation and Configuration Guide
Release 3.0, Part Number OL-2521-01 Rev. D0, June 2004
Chapter4 Configuring VISM Features
Configuring Additional VISM Features
Mid-Call DTMF
The mid-call dual tone multifrequency (DTMF) feature enables the collection and notification of digits
to the call agent following a call setup for an endpoint, and suppor ts the outpulsing of DTMF digits at a
call agent’s request. This feature is used for services that require two stage dialing, such as calling card
applications.
Mid-call DTMF is supported for all the CAS variants, for DTMF mode only.
Configurable Jitter Buffer
The configurable jitter buffer feature provides configuration of jitter buffer mode and initial delay time
on a codec basis. Fax, modem, and CCD calls have less packet loss with the addition of this feature.
Adjustable Gain
The adjustable gain feature allows you to adjust gain on a DS0 channel basis for both input and output
signals. The adjustable gain can be set when there is active call going on at the DS0 channel, a nd at both
bounded non-active and unbounded endpoints.
Adjustable Music On-Hold Threshold
The adjustable music on-hold threshold feature allows you to adjust the dB level, on a DS0 basis, of
when DSPs interpret TDM side silence or voice.
CALEA
The Commission on Accreditation for Law Enforce me nt Ac t ( CA LE A) fe atur e, u sed w it h VoIP
applications, provides data (eavesdropping) about an intercepted subject (the user/subscriber) in two
forms for both the receive and transmit directions:
•Call identifying data
•Call content data
The call identifying data (called number) is provided by call agents. The call content data (voice) is
provided by the edge/access routers (7200, for example) and trunking gateways (MGX 8000 series
platforms) in combination with VISM cards.
The VISM CALEA implementation supports the CALEA law intercept confirmation interface.
MGC Redundancy
The media gateway controller (MGC) redundancy feature provides redundan cy for call agents on VI SM
cards. You can associate one or more call agents as members of a redundancy group.
An MGC redundancy group consists of one or more MGCs (whic h are identified by their domain name).
An MGC can be part of one redundancy group, although there can be multiple MGCs per redundancy
group. At any given time, only one MGC in the redundant group is act ive.