Monthly Archives: October 2012

Just Say It

I recently built a voice response system with Voxeo‘s software: their VoIP IVR (Prophecy) and VoiceXML server (VoiceObjects).  This stack is available in both on-premise (local install) and cloud versions (Evolution/VoiceObjects on Demand), and includes an Eclipse-based development environment, VoiceObjects Desktop for Eclipse (DfE).  VoiceObjects (VO) takes a little getting used to, but is a nice platform for developing call flows.  It sure beats hand-coding VoiceXML, and it integrated well with my Java service back-end.

VoiceObjects’ documentation is excellent, but I learned quite a lot by trial and error.  So I thought I’d share a few tips and lessons learned.

Use scripts and expressions

VO’s library of objects is quite rich, but you will inevitably run into some requirement that needs more than just objects with properties.  For example, I used nested concatenate expressions to build complex types for web service calls; split, index, findcell, strequal, and matchesregexp expressions to process web service results; and JavaScript to handle custom DTMF mappings. The prepackaged expressions are also helpful, such as the ones that grab ANI and DNIS from session state.

Set event handlers

It’ll take about 5 seconds to grow weary of the thickly-accented “service you are trying to reach is not available…” default message.  Get a friendlier message with more root cause details by setting the event handlers in your top-level module (they’ll be inherited by child objects).  Just open the Outline view, expand Event Handling section, and add away.  You can add whatever outputs you’d like, and use different handlers for repeat occurrences.

Set default routing

Be sure you have a default routing (*) entry in the Prophecy Commander applications list, since surely someone will use the wrong SIP address or configure the wrong URI.  With a default routing entry, callers at least land in a recognizable place.

Get Blink

VO’s built-in SIP Phone is very basic, so you’ll find yourself looking for alternatives.  There are a lot of free SIP phones out there, but most require signing up to a service or can otherwise violate corp-rat security concerns.  I settled on Blink.  It’s a little buggy, but does the job.

Get an ATA

SIP phones are handy, but you’ll eventually want to pick up a POTS phone or cell and call into your IVR.  While you can can assign PSTN phone numbers in Evolution/VoD, that doesn’t help with your local Prophecy install.  That’s where Analog Telephone Adapter (ATA) gateways come in.  I used the AudioCodes MP-114; the model with two FXO and two FXS ports provides both analog in and analog out options.

Get the latest version

Since Voxeo’s hosted environment uses VO 10, I started out with that version.  But I quickly ran into some problems that required recent fixes.  Voxeo was kind enough to build a custom VO 11 environment in an AWS instance for my cloud testing, but their GA hosted platform will be upgraded soon.  In the mean time, there’s really no reason not to use one of the recent versions: 11 or 12.

Add debug outputs

VO provides a Log object for tracing purposes, but I often found it easier to use additional Output objects to hear trace messages on the call.  By convention, I labelled these with a “Debug – ” prefix, and disabled them (but left them in place) when not used.

Use the logs

Even minor typos can cause VO to throw internal exceptions that leave you scratching your head.  Sometimes you can diagnose these with Debug and Trace, but in most cases the VoiceObjects logs (viewable from DfE) provide the best information.   If the problem is on the IVR side, use Prophecy’s built-in Log Viewer to hunt down the root cause.

Use the support forums

For some vendors, support fora are where problems go to die from neglect.  But that’s far from the case with Voxeo.  They have an excellent support team that quickly responds to issues.  You can browse existing posts for common problems and easily add new tickets.