Opportunities in Deploying Open Source Applications Using LumenVox Speech Recognition on Asterisk

3 About Asterisk Open-source PBX Initially written by Mark Spencer, founder of Digium Maintained by Digium –Open Source, licensed under the GPL –Business Edition, licensed under a commercial license

4 About LumenVox Core speech recognition technology –Designed for use in telephony/IVR environments C/C++ API and MRCP Windows and Linux

5 Asterisk + LumenVox Digium wrote a connector bridge –Included with Asterisk Business Edition –Available as a download for Asterisk Open Source Ties Asterisk generic speech API into LumenVox’s API Allows the easy addition of speech to Asterisk applications

6 Why Add Speech? Speech recognition allows easier access to traditional IVR applications –Hands-free use –Fewer DTMF nested menus to navigate Speech recognition allows new types of applications –Flexibility and low cost of implementation allows developers to build new and interesting speech solutions running on an open source stack

7 Implementing Speech Create grammars –Structured list of words that can be recognized at a given prompt –Also can contain considerable logic to control output Set various parameters Stream audio Get results

8 Adding Speech to Asterisk Install LumenVox Speech Engine and the Asterisk/LumenVox module Prepare grammars and prompts Use Asterisk speech functions –Initialize a connection with SpeechCreate() –Activate grammars –Play a prompt while listening for speech –Evaluate results

9 Example Asterisk Speech App Asterisk dialplan of simple yes/no speech application: exten => s,1,Answer exten => s,2,SpeechCreate() exten => s,3,SpeechActivateGrammar(yesno) exten => s,4,SpeechBackground(confirm.gsm) exten => s,5,Verbose(1|Result was ${SPEECH_TEXT(0)})

10 Case Study: iPlateU Web 2.0 meets Asterisk: –iPlateU allows drivers to call the system and say the license plate of a car, exchanging messages with other drivers via the Web site. iPlateU would be impossible with DTMF: –Cannot enter alphanumeric characters, cannot use while driving. iPlateU provides its grammar as open source to other users to capture alphanumeric characters.

11 Case Study: Magic Button FreePBX is a very popular Asterisk configuration tool. Key people in that project developed the “magic button” for Asterisk+LumenVox: –Allows users to press a button during a call, say a command, and have it executed. Good example of commercial application being built on top of open source architecture.