Redial: Interactive Telephony

Shawn Van Every
Wednesday 6:30 PM - 9:00 PM
Fall 2006

Important Resources:

Syllabus (this page):
ITP Telephony Listserv:
Class Wiki:


Office Hours:

Tuesdays and Thursdays 12 PM - 2 PM


20% Assignments
25% Class Participation/Attendance
25% Final Project
15% Midterm
15% Presentation


Mandatory, unexcused absences will affect your final grade. If you are going to be absent, please let me know ahead of time if you can.


Excessive lateness will affect your grade. Don't be late.


Laptop use is prohibited while other students are presenting or during discussion. While I am lecturing you may use them for note taking or class related work. In other words, respect your fellow students and don't check your email.



Asterisk The Future of Telephony - O'Reilly - Jim Van Meggelen, Jared Smith and Leif Madsen
(Published under Creative Commons and available online at:
Wired for Speech - How Voice Activates and Advances the Human-Computer Relationship - Clifford Nass and Scott Brave


Asterisk Documentation Project
O'Reilly Emerging Telephony


This class will have weekly homework assignments, readings along with a midterm and final project. All are required. Failure to do assignments or participate in class discussion on readings will adversely affect your grade. Assignments will be posted on syllabus each week. Please check syllabus for current assignment even if they aren't mentioned in class.


VoIP and Internet Telephony are fast moving areas. Telephony in general has a long history and has had dramatic effect on culture and society around the world. Unfortunately, 14 weeks is not enough time to cover all of the emerging technical aspects nor the rich cultural and societal impact that telephony has had. In order to add more variety into the course material each student will be assigned to a group to give a short (15 minutes maximum) presentation on one historical, cultural, societal or emerging technical aspect that we are not covering in course material.

Weekly Rundown:

Week 1 - September 6

Introductions: Syllabus, Examples, VoIP basics and Asterisk
  • Find some interesting examples of using the phone for performance, information retrieval, social purposes and so on. Add them to the class wiki and prepare to dial or otherwise show in class.
  • Get up and running with your Asterisk account on Social. Try some simple commands in your Dialplan such as Echo, SayDigits, Background, Wait, and so on. Use the Asterisk book or as a reference.
  • Reading:
  • Chapters 1 and 5 (Ignore "Using the Dial() Application") of Asterisk: The Future of Telephony

  • Week 2 - September 13

    Asterisk 101: Voicemail, Manager Interface, Basic Unix and more with the Dialplan
  • Get comfortable with Voicemail
  • Explore the Dialplan
  • Build a Voicemail like system with the Dialplan
  • Reading:
  • VoIP Hacks Handout
  • Chapters 5 (again), 6, 11 and appendix B of Asterisk: The Future of Telephony

  • Week 3 - September 20

    Softphones and Dialplan Continued: Core Concepts, Advanced Commands
  • Get up and running with a softphone, try out the more advanced commands from this week.

  • Week 4 - September 27

    Programming Asterisk: PHP 101, AGI Scripting
  • Get familiar with PHP programming and try some simple AGI scripting.
  • A good plan might be to try writing an AGI script that has the server read the time and temperature.

  • Week 5 - October 4

    Programming Asterisk Continued
    Bridging to the Web
  • Brainstorm for Midterm

  • Week 6 - October 11

    Other Topics in VoIP: IP Phones, WiFi Phones, ATAs and more.
    Midterm Workshop and Review
  • Midterm Work

  • Week 7 - October 18

    Show Midterms

    Week 8 - October 25

    Speech Synthesis (Festival)
  • Try using Festival in one of your projects, try out the different voices and what can be done with SABLE
  • Read Chapters 1 through 4 in Wired for Speech

  • Week 9 - November 1

    Speech Recognition (Sphinx)
    Guest Presentation: Hacker Community
  • Try using Sphinx.
  • Read Chapters 4 through 8 in Wired for Speech

  • Week 10 - November 8

    Controlling Devices by Phone (by Network)
    Guest Presentation: VoIP Community
  • Decide on and prepare final project proposal
  • Finish up Wired for Speech

  • Week 11 - November 15

    Final Project Proposals
    Additional Topics

    Week 12 - November 29

    Final Project Workshop 1
    Additional Topics

    Week 13 - December 6

    Final Project Workshop 2
    Additional Topics

    Week 14 - December 13

    Let's See it! Show final projects, Expect guests

    Additional Topics (depending on time):

  • Phreaking
  • VoiceXML
  • iChat/AIM/Skype/GTalk/Yahoo Messenger and the like
  • Emerging VoIP Topics: Presence, Web 2.0 APIs and whatever else comes up
  • SIP to SIP dialing and IP only phone networks (Free World Dialup, ENUM)
  • Basic Telephone Electronics
  • Asterisk 1.4, Asterisk GUIs