The
Motorola VoxGateway: Lessons Learned
A
Bit of History
The concept of browsing web content by voice over ordinary
phones was developed in the mid-1990s, mainly at AT&T
Bell Labs. Soon afterwards, Lucent, the spun-off
equipment manufacturing arm of AT&T, began to commercialize
voice browsing in their Lucent Speech Server.
At the same time, Motorola made a huge push into the
voice web with their Mobile Internet Exchange (MIX)
voice platform. By 1998 Motorola announced it
publicly, and had made available a free companion software
development kit, the Mobile Application Development
Kit (MADK), that used Microsoft speech technologies
and was downloaded by 50,000 developers. MIX was
hugely influential, and generated a lot of press, including
one front page article in the Wall Street Journal that
inspired me to join Motorola in early 1999.
One
of the key features of MIX was Motorola's new VoxML
voice markup language (a precursor to VoiceXML), designed
by Dave Ladd and Pat McClaughry. The MIX architecture
supported two kinds of voice applications. For
applications that were used intensively, such as voice
activated dialing, MIX provided a highly compact and
efficient Java voice applet ("Vlet") interface.
For all other applications, where the ease and flexibility
of web-based development and deployment were critical,
there was VoxML.
The first VoxGateway was a VoxML voice browser developed
in 1997-1998, and used in both MIX and the MADK.
It was written in Java, a fairly gutsy choice for the
time. To the MIX voice platform, the VoxGateway
looked just like any other Java Vlet.
But at least by late 1998 is was clear that the VoxGateway
would need a complete rewrite. Time to market had
been critical, and the developers of the first VoxGateway
had had to make certain simplifying assumptions.
It was thus:
- deeply connected into MIX-specific Vlet APIs;
- hard-wired to the Nuance speech recognition system;
- required Windows NT 4.0 as the underlying operating
system (e.g., it used the Internet Explorer "wininet"
library to do web page fetching); and
- designed to support only VoxML.
Motorola wanted to license the VoxGateway source
to other companies in order to help boost the new voice
web ecosystem. For this reason the use of the
MIX Vlets APIs was problematic, as were the assumptions
that the VoxGateway would always run on Windows and
use Nuance. But the chief reason for a rewrite
was that the voice web also needed a new standard markup
language to begin growing, so the VoxGateway had to
be reengineered to support the old VoxML and the new
VoiceXML voice markup language.
In
the rest of this article, I'd like to describe the new
VoxGateway and how it met these challenges, and share
tips for other voice browser developers.
Continued...
back
to the top
Copyright
© 2001-2003 VoiceXML Forum. All rights reserved.
The VoiceXML Forum is a program of the
IEEE
Industry Standards and Technology Organization
(IEEE-ISTO).
|
