Communication between the VXML Server and Voice browser is based
on request-response cycles using VoiceXML over HTTP. VoiceXML documents are
linked together by using the Uniform Resource Identifiers (URI), which is a
standardized technology to reference resources within a network. User input is
carried out by web forms similar to HTML. Forms contain input fields that the
user edited and sent back to a server.
for the Voice browser are located on the VXML Server. These resources are
VoiceXML files, digital audio, instructions for speech recognition (Grammars),
and scripts. Every communication process between the VoiceXML browser and Voice
application has to be initiated by the VoiceXML browser as a request to the
VXML Server. For this purpose, VoiceXML files contain grammars that specify
expected words and phrases. A link contains the URL that refers to the Voice
application. The browser connects to that URL as soon as it recovers a match
between spoken input and one of the grammars.
From Unified CVP
Release 9.0(1) and later release the CVP installer installs CVP Call Server,
CVP VXML Server and Media Server together. On installing CVP installer, you can
configure only Call Server, VXML Server, Media Server or any other combination
When determining the VXML Server
performance, consider the following key aspects:
QoS and network bandwidth
between the Web application server and the voice gateway
Use of prerecorded audio
versus Text-to-Speech (TTS)
applications tend to use prerecorded audio files wherever possible. Recorded
audio sounds better than TTS. Prerecorded audio file quality must be designed so
that it does not impact download time and browser interpretation. Make
recordings in 8-bit mu-law 8 kHz format.
Audio file caching
Ensure that the voice gateway
is set to cache audio content to prevent delays from downloading files from the
media source. For details about prompt management on supported gateways, see
Cisco IOS Caching and Streaming.
Use of Grammars
A voice application, such as
any user-centric application, is prone to certain problems that might be
discovered only through formal usability testing or observation of the
application in use. Poor speech recognition accuracy is one type of problem
common to voice applications, and a problem most often caused by poor grammar
implementation. When users mispronounce words or say things that the grammar
designer does not expect, the recognizer cannot match their input against the
grammar. Poorly designed grammars containing many difficult-to-distinguish
entries also result in many incorrectly recognized inputs, leading to decreased
performance on the VXML Server. Grammar tuning is the process of improving
recognition accuracy by modifying a grammar based on an analysis of its
Cisco IOS Voice Browser or the Media Resource Control Protocol (MRCP)
specification does not impose restrictions on support for multiple languages.
However, there may be restrictions on the automatic speech recognition (ASR) or
TTS Server. Check with your preferred ASR or TTS vendor about their support for
your languages before preparing a multilingual application.
dynamically change the ASR server value by using the
property com.cisco.asr-server command in the VoiceVXML script. This
property overrides any previous value set by the VoiceXML script.
Cisco Unified Call
Unified Call Studio is an Integrated Development Environment (IDE), which needs
to be installed in a setup that is conducive for development, such as
workstations that are used for other software development or business analysis
purposes. Unified Call Studio is Eclipse-based, due to which development
activities such as writing Java programs or building object models can be
migrated to this tool so that developers and analysts have a common utility for
their development needs.