FAQ: How can I use the Internet as a telephone?

Newsgroups: northcoast.support , alt.internet.services , alt.bbs.internet , alt.culture.internet , alt.winsock.voice , alt.winsock.ivc , comp.sys.mac.comm , comp.os.ms-windows.apps.comm , news.newusers.questions,

comp.compression, comp.dsp, comp.speech, comp.os.ms-windows.apps.winsock.misc

Archive-name: internet-services/voice-faq
Last-Modified: 1995/10/22
Version: 0.3

FAQ: How can I use the Internet as a telephone?
Version 0.3 - Oct 22 1995

* This is a DRAFT FAQ. This document is new and in transition. If you
notice that software for doing speech over the Internet is  missing from
this list, or information herein needs updating, please send e-mail to
savetz@northcoast.com *

This document is copyright 1995 by Kevin M. Savetz and Andrew Sears. 
All rights reserved.  More legal stuff is near the end of this file.


Can I use the Internet as a telephone?
What do I need to call others on the Internet?
   How does it work?
What do I need to call others on the Internet?
How do I make calls using a modem?
Is the sound quality as good as a regular telephone?
Is there a noticeable delay in hearing the other user?
What is the difference between full duplex and half duplex?
What is multicasting?
Can I talk to users of other phone software?
What software is available?
   For the Mac: Maven, NetPhone, CU-Seeme, PGPfone
   For Windows: Speak Freely, CU-Seeme, Internet Phone, Digiphone,
	        Internet Voice Chat, Internet Global Phone, Web Phone
   For UNIX: Speak Freely, nevot, vat, mtalk, ztalk
Legal Stuff
Where to Find this Document


Yes. In recent months, several programs have become available that will
let you, equipped with the right computer hardware, an Internet
connection, and special software, to speak (voice) in real-time over 
the Internet - in effect using the network like a telephone.

Some of the programs available to do voice on the 'net is free, others
are commercial. Many of these products are ready for prime time, but
others are still very experimental.


It's magic! Audio conferencing programs work by digitizing your speech as
you talk and sending the digital data over the Internet. But there's a
problem: a typical modem connection has limited bandwidth - 14.4KBPS
modems can send and receive a maximum of 1,800 bytes of non-compressible
data each second. Telephone quality speech needs 8,000 bytes per second
of bandwidth. There are two solutions to the problem: get more
bandwidth, or compress the sound information before transmitting it.
Although both solutions are used, most programs compress the audio. 

There are a variety of methods for encoding and compressing sound data,
and as you might expect, the standards aren't necessarily very standard,
yet. The quality of the audio you'll send and receive depends on the
application you're using, the speed of your computer and the compression
method used. In my tests, audio is usually understandable, albeit less
clear than a phone call. Still, talking across the country or around the
world for the cost of an Internet connection is kind of amazing, and
easy on the wallet.

You and the associate you are talking to need to be using software that
can transmit and receive the same protocol. That doesn't necessarily
mean you need the same software, or even the same type of computer. For
instance, the GSM protocol is pretty standard. However, some programs
can only use proprietary encoding methods, so they'll only communicate
with the same software on the other side of the wire. Standard
compression methods are:
     GSM: for more information: http://www.cs.tu-berlin.de/~jutta/toast.html
     RTP: Real Time Protocol

What do I need to call others on the Internet?

Besides the software, you will need an Internet connection  You'll also
need a fairly speedy computer(25 Mhz).  Although the exact specs vary from 
program to program, a Mac Classic or a PC XT generally won't do the trick :-) 
Your computer will a sound card with speakers and microphone. All sound cards 
will have a microphone jack in the back of them.

What do I need to do voice conferencing on the Internet with a modem?

All you need is a version of Winsock and a SLIP/PPP connection.  The bare 
minimum for good quality sound is a 14.4k modem.  The quality of a 14.4k 
connection will depend largely on the software and the error rate of your 
telephone line.  A 28.8k modem should give excellent quality for most all 

Is the sound quality as good as a regular telephone call?

Surprising to most people, if you have a good Internet connection then
the sound quality is comparable to a regular phone call.  However the sound
quality varies dramatically between applications and depends largely on the
local capacity at each end.  In nearly all cases, the limiting factor will
not be the speed and capacity of the Internet, but will depend on the local 
work at each end.  If you have a good local network connection then some 
applications give sound quality significantly better than a regular telephone
call because they use 16 bit signals rather than 8 bit signals in regular 
phone lines.

Is there a noticeable delay to hear the other user?

The answer to this also depends on the application and local connection.  
For most applications, you might notice a delay if you try really hard, but
for good connections it seems be in the range of .01-.05 seconds.  A delay over
.05 seconds might be noticeable on the normal telephone system because you will
hear an echo, but calls over the Internet are sent differently do not produce 
an echo.

What is the difference between full duplex and half duplex?

In a full duplex conversation, you can speak and hear the other person at 
the same time.  In half duplex, only one person can speak at the same time,
and if you speak while the other person speaks, then you will not be able to 
hear each other.  In these applications, you usually press a button to speak
Most applications are starting to support both full duplex and half duplex 
modes.  Your sound card will either be full duplex or half duplex, which 
will control which mode you can operate in.  Most new Macs and many Unix
stations come equipped with full duplex sound cards, but most PC's do not.
When you load the application, if it does not let you choose full-duplex
mode, then you probably have a half duplex card.

What is multicasting?

Multicasting allows one user to send packets to several users for conferencing.
The M-Bone is overlay on the Internet that will allow one site to broadcast
to many users minimizing bandwidth usage.  In addition to being used for voice
conferencing, multicasting can be used to make the Internet a broadcast service 
to allow users to hear live radio broadcast or even see live video of events like
Space Shuttle launchings.

Can I talk to users across PC/Mac/Unix platforms?

Yes. Speak freely offers full compatibility between Windows and Unix users. CU-Seeme offers full

compatibility between Mac and PC users.

Can I talk to users of other phone software?

Maybe.  To talk to others using different software you need to have the 
same type of connection scheme and the same type of compression.  There 
are two standards emerging for establishing connections that are emerging, 
VAT and RTP which are compatible with each other.  Since VAT was the first 
working voice conferencing program, many other applications have mimicked 
its method of establishing a call.  Programs using RTP will use the same 
connection procedure but will have added capabilities to control call quality.  
Those applications that conform to the RTP/VAT standard include Maven, 
Netphone, Vat, Nevot and soon Speak Freely.  GSM seems to be emerging as 
the compression standard and is supported by Maven, Netphone, Speak Freely,
Internet Global Phone and Nevot.  There are also slight variations between
the compression algorithms that might still cause compatibility problems.
If you are using a commercial product with proprietary compression, then 
you are out of luck because you will not be able to talk with others 
because they want everyone else to buy their software.


For the Mac


Maven was the first Internet audio conferencing tool for Macintosh. Maven
is free software, but it is a bandwidth hog. Maven requires a minimum of
16KBPS, so even in its lowest quality sampling mode, it requires just a
little bit more bandwidth than a 14.4KBPS modem can give you. The
program can talk to other Macs running Maven, as well as the UNIX vat
program.  For those who have the bandwidth capabilities, it probably
offers the best sound quality for a Mac.

Platform: Macintosh, 16BPS of bandwidth
Encoding/compression: vat or Maven-proprietary
Features:  Full/Half Duplex
Negatives:  Uses more than 14.4k of bandwidth
Mailing list: send e-mail:
     To: listserv@cnidr.org
     Body: subscribe maven your name
Software: ftp://sunsite.unc.edu/pub/packages/infosystems/maven
Cost: free


NetPhone, like Maven, it gives an Internet-connected Macintosh the
ability to do audio conferencing. But NetPhone works over slower
connections, even with a 14.4KBPS modem. At a sampling rate of 10,000
samples per second, the sound quality isn't wonderful, but the voice of
my NetPhone compatriots are certainly understandable. There's a free
demo version of NetPhone available that limits calls to 90 seconds.

Platform: Mac LC or faster, 14.4KBPS modem
Encoding/compression: vat, CVSD, GSM
Features: User Directory, Full/Half duplex, Good Compatibility/VAT compatible
	   WWW Compatible
Negatives:  often has poor sound quality, demo only last for 90 seconds
E-mail: netphone-orders@emagic.com
Web page: http://www.emagic.com/
Software: http://www.emagic.com/
Cost: $75 per copy, or $125 for two copies. Free demo.


This product comes from the makers of the PGP encryption scheme.  It is
currently only available in beta format for Macs, but a Windows 95
version will be available soon.  The encryption scheme used in the application
is banned for US export, and because of current lawsuits against the makers 
of PGP, users outside the US must use a different version.  The current 
version only supports full duplex sound cards.
Encoding:  PGP
Features:  Good encryption
Negatives:  Only beta version, Only full duplex sound cards supported
Web page: http://web.mit.edu/network/pgpfone/
Cost:  Free

CU-Seeme for Mac

(see description in Windows section)

For Windows


Speak Freely is written John Walker, the founder of Autodesk.  It is
free and one of the best applications available.  It offers 
many features more advanced than commercial software such as
 voice mail, multicasting, encryption, and usually offers the 
excellent sound quality.  Its GSM compression routine requires a high-end
486 or Pentium processor.  Will work for 14.4 modems with GSM, but sound 
quality is degraded.  Current version is not compatible with other software 
except for Speak Freely for Unix.  Version 6.0 will be compatible with the 
VAT/RTP standard and will include DVI4 and L16 compression and will include a 
user directory accessible from within the application and on the WWW.
The complete source code is also available.
Platform: Windows 3.1, 386 Enhanced Mode, Winsock, 14.4KBPS modem
Encoding/compression GSM, ADPCM, PCM, PGP, DES, IDEA.  
Features:  Voice Mail, good variety in compression/encoding, excellent sound
	quality, Full/Half Duplex, multicasting for conferences, WWW compatible
Negatives: sound quality is marginal over 14.4k modems
E-mail: kelvin@fourmilab.ch
Web Page: http://www.fourmilab.ch/netfone/windows/speak_freely.html
Software:  Windows (http://www.fourmilab.ch/netfone/windows/speakfb.zip )
	    and Unix (http://www.fourmilab.ch/netfone/unix/speak_freely-5.3.tar.gz)
Voice Chat Room: http://rpcp.mit.edu/~asears/voice.html
Cost:  Free


CUSeeMe is a project of  Cornell University for audio and video conferencing 
over the Internet.  Sound quality is good, but might have problems with a 
14.4k connection.  Viewing images is impossible at 14.4k and is slow and 
28.8k, but audio conferencing will work without images.  Users can transmit 
images using a camera that can be purchased for as little as $99, but 
a camera is not needed.   One main advantages of CU-Seeme for audio 
conferencing is that users can either connect directly to each other or 
they can enter a conference at a reflector.  In addition, CU-Seeme 
probably offers the best compatibility with other applications.
Features:  Good conferencing capabilities, and allows for video conferencing,
	    good sound quality, compatible across Windows/Mac, WWW compatible
Negatives:  Need at least a 28.8k connection
Web Page: http://cu-seeme.cornell.edu/
Listserv: Send message "Subscribe CU-SEEME-L Firstname Lastname" 
	   to LISTPROC@cornell.edu
Software: http://cu-seeme.cornell.edu/get_cuseeme.html, Windows, Mac & Power Mac


Internet Phone runs on top of Internet Relay Chat, providing you with a
list of on-line users and topics of conversation, making it easy to find
new people to chat with. Quickly becoming one of the most used applications
because the software makes it easy to find others to talk to.  The main
disadvantage is that that the software is one of the few application that
only offer proprietary compression scheme, which makes it impossible for
it to be compatible with other applications.  The test version only allows 
for one minute of conversation before it times out.

Platform: Windows 3.1, 33 MHz 486 or faster, Winsock 1.1, 14.4KBPS modem
Encoding/compression: Internet Phone proprietary
Features:  Excellent user directory, full/half duplex, low bandwidth demands
Negatives: Demo limited to one minute, not compatible with any other software,
	    Cannot make connections without using IRC
E-mail: info@vocaltec.com
Web page: http://www.vocaltec.com/
          User directory: http://www.pulver.com/
Software: ftp://ftp.vocaltec.com:/pub (one minute demo)
Listserv: Send Message "subscribe iphone" to majordomo@pulver.com
Cost: $99


This is application just recently was made available.  Because they do not
offer a test version, little is known about how effective it works.  
According to news releases they had preorders totaling over $1 million.  
Digiphone can come by itself or in a complete package which includes
a Web browser, E-mail, telnet, FTP, voice messaging and caller ID.
While it seems that they have invested heavily in advertising, they
offer no WWW distribution of their product.
Features:  Good integration with other Internet applications
Negatives:  not available on the Internet, not compatible with other software
E-mail: custserv@planeteers.com
Web page: http://www.planeteers.com/
Software:  None Available on the Internet
Compression:  Proprietary
Cost:  $89.95 alone or $149.94 w/ complete package


Internet Global Phone is not a clean, ready-to-use application. In fact,
it is very much a work in progress. Internet Global Phone is a
"technology demonstration project" providing a code platform for two way
real-time voice exchange over the Internet. The details of the project
are documented in an article in Dr. Dobb's Journal in December 1994. If
you like hacking in Microsoft Visual C++, you too can hack on Internet
Global Phone. IGP currently lacks a real user interface, but it really more
useful for people to look at the source code in Visual C++. 

Platform: Windows 3.1, 20 MhZ 386 or faster, 14.4KBPS modem
Encoding/compression: GSM
E-mail: lsing@tor.hookup.net (Sing Li)
Software: ftp://ftp.cica.indiana.edu:/win3/demos/IGP*
Source code: ftp://ftp.cs.tu-berlin.de:/pub/local/kbs/tubmik/gsm/ddj
Cost: free


Internet Voice Chat provides almost - but not quite - real-time
communication. Unlike other communications programs, it doesn't send
sound as you speak -- it waits until you finish to compress and send the
sound. The result is a slower-paced conversation with frequent gaps.
(On-the-fly compression is planned for a future version.) Once the
shareware is registered, the program includes features line an answering
machine and call screening functions.

Platform: Windows 3.1, 386 or faster, Trumpet Winsock 2.0B, 14.4KBPS
Encoding/compression: Internet Voice Chat proprietary
E-mail: ivcsupp@aol.com
Newsgroup: news:alt.winsock.ivc
Web page: http://futures.wharton.upenn.edu:80/~ahrens26/ivc.html
Cost: shareware, $25


Webphone is an unreleased product of Quarterdeck.  Their aim will be to
integrate Webphone with their Web browser.
Not Yet Released
Web page: http://www.qdeck.com/qdeck/press/webphone.html
Cost:  Less than $50


Speak Freely for Unix

(See Version information above in the Windows Section)


NEVOT (Network Voice Terminal) provides voice communications using
unicast, simulated multicast or IP multicast, using the vat or RTP
protocols. Requires a high-end workstation.

Encoding/compression: vat, RTP, GSM, LPC
Platforms: SunOs 4.1, Solaris 2, Irix, HP/UX
Features: RTP/VAT compatible, good controls, WWW compatible
Web site: http://www.fokus.gmd.de/step/employees/hgs/nevot/nevot.html
Software: ftp://gaia.cs.umass.edu/pub/hgschulz/nevot
Cost: free


Vat was the first audio conferencing tool for the Internet. Requires a
high-end UNIX machine.  The VAT standard for setting up a call is quickly
becoming the dominant standard along with RTP, which will allow users of
different applications to communicate.

Encoding/compression: vat
Platforms: Sun Sparcstation, Silicon Graphics and DECstation 5000
Software: ftp://cs.ucl.ac.uk/mice/videoconference/vat/
Cost: free


MTALK is an "very alpha" experimental voice-talk system for LINUX. It
uses low bandwidth (approx. 1 KBPS) and claims to work even on computers
with very low bandwidth connections. Requires a LINUX workstation with a
Soundblaster compatible sound-card. 

Encoding/compression: unknown
Platforms: Linux
E-mail: misch@elara.fsag.de
Software: ftp://sunsite.unc.edu/pub/Linux/apps/sound/talk/
Source code: ftp://sunsite.unc.edu/pub/Linux/apps/sound/talk/
Cost: free


Simple, "Extremely alpha" voice software for Linux. Includes a voice mail

Encoding/compression: GSM
Platforms: Linux
E-mail: feinmann@cs.mcgill.ca
Source code: ftp://sunsite.unc.edu/pub/Linux/apps/sound/talk/
Cost: free


This document is copyright 1995 by Kevin M. Savetz and Andrew Sears. 
All rights reserved.

Permission for the following types of distribution is hereby granted,
provided that this file is distributed intact, including the above
copyright notice:
     - non-commercial distribution
     - posting to Internet archives, BBSs and online services
     - distribution by teachers, librarians and Internet trainers
     - inclusion on software/FAQ/Internet-oriented CD-ROMs

Permission for commercial distribution may be obtained from the editor.

This document is new and in transition. If you notice that something
important is missing, or information herein needs updating, please
contact the editor.

The editor and contributors have developed this FAQ as a service to the
Internet community. We hope you find it useful. This FAQ is purely a
volunteer effort. Although every effort has been made to insure that
answers are as accurate as possible, no guarantee is implied or
intended. While the editor tries to keep this document current, remember
that the Internet and its services are constantly changing, so don't be
surprised if you happen across statements which are obsolete. If you do,
please send corrections to the editor. Corrections, questions, and
comments should be sent to Kevin Savetz at savetz@northcoast.com or
Andrew Sears at asears@mit.edu  Please indicate what version of this 
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