Speak Freely for Windows

by John Walker
http://www.fourmilab.ch/


Contents

Speak Freely is a Windows Internet telephone application that allows you to talk (actually send voice, not typed characters) over a network. If your network connection isn't fast enough to support real-time voice data, various forms of compression may allow you, assuming your computer is fast enough, to converse nonetheless. To enable secure communications, encryption with DES, IDEA, and/or a key file is available. If PGP is installed on your machine, it can be invoked automatically to exchange IDEA session keys for a given conversation. Speak Freely for Windows is compatible with Speak Freely for Unix, and users of the two programs can intercommunicate. Users can find one another by communicating with a "Look Who's Listening" phonebook server. You can designate a bitmap file to be sent to users who connect so they can see who they're talking to. Speak Freely supports Internet RTP protocol, allowing it to communicate with other Internet voice programs which use that protocol; in addition, Speak Freely can also communicate with programs which support the VAT (Visual Audio Tool) protocol.

Introduction
Hardware and software requirements

Quick Start Guide

Connections
Creating a new connection
Setting connection options
Closing a connection
Saving a connection in a file
Opening a connection file

Communicating
Receiving audio
Sending live audio
Sending sound files
Ringing remote users
Testing using local loopback
Multicasting to a group
Broadcasting to multiple sites
Conferencing
Viewing extended status
Monitoring audio levels and spectrum
Voice activated transmission
Communicating with other network audio programs

The answering machine

Show your face

Text chat

Phonebook: Look Who's Listening
Publishing your directory entry
Finding on-line users

Compression

Encryption
Why encryption?
Varieties of encryption
Generating and exchanging keys
Legal issues
Patent issues

Window display modes

Command line arguments

Problems, problems
Regular pauses in audio output
Random pauses in audio output
Compression slows down transmission
Viewing extended status
Workarounds for driver bugs

Internet resources
Speak Freely Internet mailing lists
Echo servers
Publishing your directory entry
Finding on-line users

Debugging tools
Viewing extended status
Local loopback
Remote echo mode
Monitoring audio levels and spectrum
Diagnostic console

Hardware issues
Viewing hardware configuration
Measuring computer performance
8 or 16 bit sampling?
Half- or full-duplex?

Bugs, features, and frequently asked questions

References
Speak Freely for Unix machines
Credits
Bookshelf
Development log
About the author