Cool VoIP Hacks Using Asterisk
Jim Van Meggelen from Core Telecom Innovations introduced a number of VoIP hackers to today's audience at eTel in San Francisco. Many coders are out there building front-ends for Asterisk, but they aren't hacks - they're spendy, glossy, and preconfigured. Here's some of the cooler projects discussed at show-and-tell:
Cool Hack #1: Performance Tuning for Asterisk VoIP
Kristian Kielhofner, the creator of AstLinux, showed the crowd his embedded Linux distribution for running Asterisk. This hack is important if you need your VoIP tuned for performance. First: Heavily loaded servers interfere with sound quality - but while you don't care if a web page downloads slightly slower, you may be annoyed if it happens during a phone conversation. Second: High availability. Larger-scale PBXs have redundant CPU cores, so users don't notice if one goes down. This redundant coverage is very difficult to achieve in Asterisk.
There's now an AstLinux virtual machine built with VMWare Workstation 5. This allows you to experiement with Linux and Asterisk without leaving your typical environment. This application has found a niche with people doing demos, training, or user groups.
Heartbeatd is a server daemon that checks for a "heartbeat" on other servers; if another heartbeat stops, then heartbeatd instructs its host machine to take over for the failed server. This works over both Ethernet and serial interfaces, and is supported by AstLinux. Unfortunately, if Asterisk were to crash, the daemon can't report that its own self has failed.
AstLinux-HA is most useful for VoIP-only applications, since it doesn't yet support routing.
Other limitations include Asterisk's native sounds. Christian had his pal Allison re-record all of the Asterisk sounds in the highest-quality format she could. They then converted directly into every Asterisk format. This eliminated some of the problems of transcoding into loss-based compression formats. These improved files will be publicly available in a couple of weeks.
Cool Hack #2: Playing Zork with IVR
This developer (send me his name if you know it, and I'll insert it here) is using Sphinx to develop an interactive voice response (IVR) version of Zork. You remember Zork...open the mailbox, pick up the leaflet, etc. Sphinx still has trouble with interference and clipping. (Clipping is when you lose the ends of a word, a common problem in IVR devices.)
Clipping aside...adventuring in Zork would sure be better than Muzak for killing time while in a customer support queue.
Cool Hack #3: Integrating Speech into Browsers
Ralf Muehlen stepped up with his VoIP Click2Dial. This hack begs the question...why should this application be so hard? There's plenty of multimedia integrated into browsers. VoIP Click2Dial allows browser users to drop directly into a customer service call queue, rather than having to call in separately from a telephone. This was built using Firefox, GreaseMonkey, and a web-enabled VoIP application.
Klipper is a related hack built using KDE. This could be extended to other browsers, and could also be extended beyond VoIP. If you had an interface to other telephone routing protocols, the API could be extended to include it.
Cool Hack #4: Analyzing User Navigation
Quinn Weaver stepped up from the audience to talk about Dido, a hack for analyzing user behavior and navigation through IVR or other telephony tree systems. This was actually built using XML + Perl rather than Ruby.
There were other cool hacks discussed, but the simplicity of these was pretty appealing. Check them out, and don't forget to tip your server.
Tags: christine herron spacejockeys voip technology asterisk open source o'reilly etel astlinux
Please see http://uc.org/read/ZoIP for more info on Ziop. Following frompage including author's name : Simon P. Ditner Hope this helps.
ZoIP - a telephony/text adventure bridge for Asterisk and Infocom games
ABOUT
ZoIP (formerly Zasterisk) implements a Rezrov ZIO object, allowing a user to communicate with a Z-Machine via telephony devices.
I was tinkering with Asterisk and the Festival text-to-speech engine, and wrote some short Asterisk::AGI scripts to read back live weather reports. After that, I thought I needed something more interactive to work with...
Then I had a flashback to 1996, first year university, standing in the C & O club at the University of Waterloo, where someone had just pulled out their US Robotics Palm Pilot and started up Zork. A couple of hours later, after a quick trip to the campus computer store, I was playing Zork in the palm of my hand!
Now Zork is back! Listen as the eerie voice of Festival takes you into the Underground Empire, and marvel as you explore this world with your dial pad, unlocking the secrets within! What will Asterisk bring us next? The future is open!
DOWNLOAD
ZoIP 0.2.1, September 17th, 2006
ZoIP 0.2.0, September 5th, 2006
ZoIP 0.1.0, August 7th, 2005
PREREQUISITES
A working installation of Asterisk
A working installation of Festival, and Sphinx2
Asterisk::AGI (http://asterisk.gnuinter.net/files/asterisk-perl-0.08.tar.gz)
Speech::Recognizer::SPX, Config::Tiny, Proc::Daemon
REVISION HISTORY
0.2.1 September 17th, 2006
Had to remove Zork gamefile, as it's not freeware/abandonware
0.2.0 September 5th, 2006
Added Sphinx2 support
Added support for Cepstral.com TTS voices
Added configuration file and removed all hardcoded values
0.1.0 Summer, 2005
Implemented basic ZIO object which communicates with asterisk via Asterisk::AGI
MAKING CUSTOM LANGUAGE MODELS
Make a list of words
Submit them to http://www.speech.cs.cmu.edu/tools/lmtool.html
Download the tar file
Place the contents in share/model/lm/zork
Rename all the files to start with zork
COPYRIGHT
Copyright (c) 2005-2006 Simon P. Ditner . All rights reserved. This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.
The CMU hmm model 'communicator' has been bundled for ease of installation. (c)1999-2001 Carnegie Mellon University. See README.sphinx for license details.
Rezrov has been bundled with this package for ease of installation. Please see README.rezrov for further details concerning it.
Posted by: Peter Bassel | September 30, 2006 at 07:48 PM
I'm looking for a document about tuning asterisk.., recommendations after installation.
www.tumujer.com
Posted by: Webmaster tumujer.com | September 05, 2006 at 06:42 AM
I loved ZORK as a kid, i cant wait to try the interactive voice response (IVR) version of Zork!!! I'm so excited!!! haha,It's gonna be great!
Ellie Drey
http://www.longdistance-t1.com
Posted by: www.longdistance-t1.com | August 28, 2006 at 04:56 PM
Simon has zork reachable by phone, per hack 2. +1 712 432 7975
Posted by: trixter | June 27, 2006 at 10:19 PM
The developer integrating Zork w/ Asterisk is named
Simon Ditner (per Hack#2 above)
Posted by: mark | March 30, 2006 at 07:56 PM