So you want to develop and deploy a VoiceXML
application, but you’re not sure whether to build your own VoiceXML gateway,
buy a turnkey solution, or host your application? This article will lay out the
pros and cons when considering a VoiceASP and discuss the features, costs, and
tools provided by each of the top vendors.
A Voice ASP is similar to Web hosting company in that you
pay a pre-determined fee that gives you access to their equipment and Internet
connection. In the case of VoiceASPs, you typically will pay a setup fee and
per-minute usage fee, similar to your long distance service. You are
provided with a toll-free or local number that your customers call to access
your applications. The VoiceASP handles all of the incoming calls
and interacts with the VoiceXML pages and applications on your Web server.
To reduce the time it takes for the Voice ASP’s gateway to interact with
your Web server, you can usually co-locate your server at the same data
center that contains the equipment that will be handling your calls. We will be
looking at the top three Voice ASP providers: BeVocal, Tellme, and Voxeo.
Voice ASP benefits
Building your own VoiceXML gateway solution is not
only complex, it’s also expensive. Even if you do have the in-house expertise, building a gateway
from scratch will cost at least $10,000 for as few as 4 ports (phone
lines). Furthermore, if you experience a fluctuating call volume, you might
have to purchase your equipment based on these peaks, which could mean that it only
gets fully utilized five percent of the year. Voice ASPs also eliminate the maintenance
costs, which usually far exceed the cost of the equipment and
software. Furthermore, the three VoiceASPs that we’re looking at, Tellme,
BeVocal, and Voxeo, include Web-based tools to help you develop and
troubleshoot your applications. And add the fact that your out-of-pocket cost to start developing and testing applications with all three ASPs is $0. The benefits of
using a VoiceASP become very compelling, but before you sign up, let’s look at
some of the drawbacks and limitations that you’ll have to address when you
consider using a Voice ASP.
Voice ASP limitations and drawbacks
When evaluating whether you should use a Voice ASP, you need
to consider the drawbacks. Part of your infrastructure might be in another
location so this could cause problems if the Internet connection between
the provider’s gateway and your Web server is interupted at any point. Also,
when using an ASP, you are stuck with the functionality that they provide. Each
ASP has a different set of features. One might support the latest standards
while another lags 6 months behind. Another drawback to using an ASP is the lag
that is related to the time it takes the ASP’s gateway to perform a transaction
with your Web server, which might be on the other side of the country.
on the lag at the time, customers might be waiting several seconds before they
hear back from the server. Even worse, they might hear nothing. Additionally,
your provider doesn’t maintain a low enough utilization rate, your customers
might be welcomed by a busy signal because other customers are saturating all
the inbound ports.
What you need to ask
The first thing you need
to consider about using a Voice ASP, especially when
the application they’re hosting is critical to your business, is that you
will be depending on a third party whose equipment and staff are out of sight.
Make sure that both you and the ASP have an agreed upon quality of service
agreement. How long is it ok for customers to not be able to reach the
application? If it’s critical to your business, it’s never ok, so does your ASP
have a guarantee of service clause? All of the Voice ASPs are partnered with
major telecommunications providers like AT&T, who provide the basic
telecommunications infrastructure, but you will still want to get information
about utilization rates for their VoiceXML gateways. You don’t want customers
ever get a busy signal and you want to be able to scale call volume for
promotions or special events. You will also want to ask about outbound call
support if you expect that you will ever to need to make outbound calls in
addition to inbound calls.
Expect to pay anywhere from $0
to $30,000 to get started with an ASP. The
setup fee is based upon your expected usage. Once you’re set up, you should
expect to pay from thirty to fifty cents per minute for usage. It’s billed much
in the same way that you pay for regular long distance service, except the cost
per minute will be higher. Tellme caters to larger customers, which will
probably also charge the highest setup cost and expect you to have a high call
volume. Tellme is also the most well established Voice ASP, offering a myriad
options for larger customers. Voxeo, being the smallest of the three, is
able to cater to smaller customers.
All three of the
Voice ASPs use Nuance software for speech recognition. This
means that you will be able to use GSL grammars with any of the providers.
Tellme and BeVocal have their own VoiceXML interpreters, which means that there
are certain features that may not be well supported or extensions that each has
made that isn’t part of the standard. Voxeo utilizes the VoiceXML interpreter
from Nuance, which means that if you use Nuance development tools, you can be
fairly sure that your application will work with Voxeo. As of thus writing,
BeVocal is the only ASP that currently supports VoiceXML 2.0. I’m fairly
that the other will support the new draft of VoiceXML shortly.
BeVocal provides the best set of development tools,
though Tellme is a
close second. Voxeo does provide a Windows application for building VoiceXML
though, which can be helpful if you’re aren’t online since the others are
strictly Web based.
If you are a small to medium
sized business, your best bet is Voxeo. If you
are a larger company that needs advanced features and good support, Tellme
is probably the one. If you want the best tools and best support for new
standards and technology, I would select BeVocal. BeVocal has the best developer support in my opinion. Voxeo has a a great
VoiceXML-like language called CallXML, which makes it easy to perform advanced
call control and place outbound calls. Tellme has good call center and IVR
integration. The best thing to do is sign up for all three and test them
- Bevocal Cafe’ – http://cafe.bevocal.com
- Tellme Studio – http://studio.tellme.com
- Voxeo Community – http://community.voxeo.com
About Jonathan Eisenzopf
Jonathan is a member of the Ferrum Group, LLC based in Reston, Virginia
that specializes in Voice Web consulting and training. He has also written
articles for other online and print publications including WebReference.com
and WDVL.com. Feel free to send an email to firstname.lastname@example.org regarding
questions or comments about the VoiceXML Developer series, or for more
information about training and consulting services.