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Answers
to Your Questions About VoiceXML
(Continued
from Part 1)
Q:
I'm interested in building my own VoiceXML platform.
What are the requirements? Can I buy all the components
separately and then put them together? What skills will
I need, and how much budget should I allocate?
A: It is certainly possible to build your own
VoiceXML interpreter and commercial VoiceXML platform.
There are at least 10 commercially available VoiceXML
platforms today. These platforms cover a variety of
deployment options:
- Outsourced.
Vendors providing outsourced VoiceXML solutions allow
customers to simply focus on writing VoiceXML applications.
Thanks to the distributed, Web-based nature of VoiceXML,
these vendors are able to run large-scale, reliable,
scalable, and secure deployments of VoiceXML infrastructure
on behalf of their customers. Customers' applications
live on their own Web servers, and the remote infrastructure
simply "browses" to the application when
calls come in. The benefit of this solution is that
customers retain full control of their applications
and data, without having to purchase or manage speech
and telephonyspecific hardware and software.
- On-premises,
"Turnkey". Vendors providing on-premises,
"turnkey" solutions sell a complete hardware/software
package to their customers for VoiceXML development.
These systems are designed to include all the requisite
hardware and software for delivering VoiceXML applications--voice
recognition engine, text-to-speech engine, VoiceXML
interpreter, telephony control cards, operating system
software, etc. Customers that purchase and install
these solutions then connect them to telecom capacity
and Internet connectivity which they've provisioned.
- On-premises,
"Software". Many vendors sell various
pieces of the overall stack required to deliver a
comprehensive VoiceXML platform solution. Platform
developers looking to create a custom solution purchase
some, build others, and link them together using customized
software and hardware.
The
skills involved in developing these solutions include
expertise in scalable server programming, telephony
programming, speech science, databases, XML, and both
Web servers and Web browsers.
It is difficult to say how much budget is required to
develop a custom VoiceXML platform; the number can shift
dramatically (e.g. several orders of magnitude) depending
on the scalability, robustness, and overall level of
functionality desired, as well as how much custom development
of underlying components you intend to undertake. It
is fair to say that most companies offering complete
outsourced or on-premises "turnkey" VoiceXML
solutions have invested tens of millions of dollars
and at least a dozen person-years of effort building
and honing their commercial-grade products.
Q: My VoiceXML platform consistently complains that
my documents must start with
"<?xml version='1.0'?>". My documents
do begin this way... what is the problem?
A: This is a common problem that VoiceXML developers
encounter. To be considered well-formed XML, the very
first line of your documents must contain the XML
declaration. Initial blank lines or extraneous whitespace
are not permitted. Be sure to remove these, and always
check your VoiceXML documents in an XML-compatible Web
browser (such as Microsoft Internet Explorer 5.x) before
running them on your VoiceXML platform. This will help
ensure that your Web server is delivering syntactically
well-formed XML before delving into any VoiceXML-specific
bugs or errors your documents may contain.
Q:
Is it possible to send voice alerts like WAP alerts?
How?
A: Yes. Several companies today (including many
of the VoiceXML Forum's member companies) offer voice
notification services that support the VoiceXML standard.
These services typically operate by allowing application
developers to submit a request using a standard HTTP
POST (or even by sending an email). The request contains
information such as the phone number to call, when to
place the call, and the URL of a VoiceXML application
to trigger when the call is made. For security and privacy
assurance, some level of security--including a company
identifier, password, and SSL or S-MIME--isalso typically
required.
Anyone who operates a VoiceXML platform can theoretically
build a notification service that provides this functionality.
VoiceXML itself does not specify a way to deliver voice
notifications, just as HTML and WML do not. VoiceXML
1.0 simply defines the interface for voice applications;
how the phone call that initiates the conversation gets
generated is a separate issue. That said, it is definitely
conceivable that a separate accepted standard that specifies
how to use HTTP, email, and other open Internet protocols
to trigger alerts across all devices including voice,
phones, PDAs, and other wireless devices will emerge
in the future.
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Copyright
© 2001 VoiceXML Forum. All rights reserved.
The VoiceXML Forum is a program of the
IEEE
Industry Standards and Technology Organization (IEEE-ISTO).
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