Sound Card Packet

Translations of this site

by  Ralph Milnes, KC2RLM
last updated: 03/30/2005 What's new on the site?
Information on this site is also available in PDF files (English only)

Most recent AGWPE version available is:
 2004.1108  (Nov. 8, 2004
(Also labeled as version 2005.127)         

AGWPE Overview
    More about AGWPE
1. Interface
 Getting Started
Kits and Pre-assembled
    Receive Audio Cable
    Transmit Audio Cable
    PTT (TX Control) Cable
    2 Radio Modification
2. AGWPE Set Up
Download and Install
    Basic AGWPE Setup
    2 Radio Setup
    2 Card Setup
3. Sound Card Setup
    Basic Settings
    Additional Settings
Tuning Aid
4. Windows™ Setup
TCP/IP Settings
    Update Windows
5. Problems?
Program Behavior
6. Using AGWPE
    AGWPE on a Network
Baud Rates & Modes
    Remote Control
    TCP/IP Over Radio
Tips and Tricks
Traffic Parameters
7. Compatible Programs
Configuration Help


This amateur radio web site explains how to use the AGWPE utility program to send and receive packet using the sound card of your PC instead of a TNC. It offers:

instructions for configuring AGWPE, Windows, and some compatible packet programs


advice about building or buying a sound card-to-radio interface


troubleshooting advice


The key to sound card packet is a free program called AGWPE. AGWPE, which stands for " SV2AGW's Packet Engine", was written by George Rossopoulos, SV2AGW.  It was originally created as a TNC management utility and has many super features of value to packet users, but this web site deals primarily with its ability to encode and decode packet tones using your computer sound card. AGWPE is the only program that I know of that can do this, other than MixW and Flexnet32. AGWPE is particularly valuable since it can act as a "host" program for several good packet programs that do not have sound card modem capabilities of their own.

Packet Engine Pro: In June 2003, George SV2AGW released a new program,  Packet Engine Pro, based on the original, freeware AGWPE program. The 'Pro' version:
bulletruns more efficiently
bullethas an improved interface
bullethas a setup 'Wizard' that simplifies new sound card (and TNC) configuration
bullethas several new features, such as Radio Port Sharing and alternative KAM-style tones for HF packet

In addition, the following features will work in PE Pro on Windows XP/2000 systems but they will not work in AGWPE on a Windows XP/2000 system (they work OK in AGWPE on a Win95/98/ME system):

bulletPTT can also be controlled with the parallel port in addition to the serial port
bulletYAM modems are supported
bulletBayCom/BayPac modems are supported, but only if your computer has legacy serial ports, i.e. non-ACPI  compliant serial ports ( ACPI is a power management/saving protocol)

The Pro version costs $49 US after a free 30 day trial period, and it will work with any program that works with the AGWPE freeware version.

I encourage you to consider the Pro version because:

bulletit is easier to use and more powerful
bulletit has features that are not found in AGWPE and may never be added
bulletyour fee supports SV2AGW's programming efforts

You can download the Pro version at:   or

This web site will continue to provide support for the freeware version, AGWPE, and aspects of it may also be helpful for Pro users.

Why use a sound card instead of a real TNC? First of all, it can be much cheaper. You only need a sound card interface, which is a set of cables to connect your sound card to your radio. Interfaces can be made for a few dollars or purchased for as little as $30-40 US, while the cheapest external TNC costs at least 100 US. And if you use the stereo qualities of the sound card to simulate two TNCs, so you could be saving the cost of two TNCs!  Other good reasons are that an interface is lighter and less bulky than a TNC and an interface usually requires no external power; a TNC will need some power source.

Another reason is that according to the program author, George SV2AGW, the AGWPE soundcard modem gives better results than a TNC .  George says the 300 baud HF modem is so sensitive that it decodes packets you cannot hear; the 1200 baud modem can decode packets even with S3 or less signal strength; and the 9600 baud modem is better than the original G3RUH. To be fair, other users claim they get better results with a TNC; that TNCs are easier to setup; and that TNCs usually have built-in watch-dog timers to prevent continuous transmitting in the event of an error.

Note that most packet programs will not work with AGWPE. Only compatible programs that have been specifically written to take advantage of AGWPE's host services will work, but there are several good ones.

The sound card features of AGWPE should work with most 16 or 32-bit sound cards, although it will not run on all cards. You should also have up-to-date drivers for your sound card; see compatible sound cards.

AGWPE will run in Windows  95, 98, ME, XP and 2000. It will not run in plain old DOS or Windows 3.1 or NT 4.0. 

Generally any Pentium II or newer processor will work. Some users have even used it on a 486, but other users have found it will not run on a Pentium I without MMX. See More About AGWPE for more information about processor requirements.

AGWPE will allow you to:

bulletUse "on air" baud rates of 300 (HF), 1200, 2400, and 9600. (See the Baud Rates and Modes page for additional info about 300 baud SSB operations and 9600 FSK operations.)
bulletUse the stereo ( 2 channel ) feature of your sound card to connect to two radios on different frequencies at the same time using just one sound card.
bullet Install additional sound cards that can be used exclusively for sound card packet. Your first sound card can then be used by Windows for other sound-producing programs and devices, such as your CD player.
bulletUse a Sound Card Tuning Aid feature for accurately tuning signals, particularly on HF, and for setting the correct RX (receive) audio volume.
bulletAccess AGWPE remotely over a network or the internet!

Getting AGWPE to work correctly can be tricky, since you will need the radio-to-computer interface with 3 wires and some circuitry, plus you'll need to configure three different programs correctly -- Windows, AGWPE, and your packet application.  Hence, this web site.  (Note that the AGWPE Help file included with the program is becoming out of date;  in some cases it is wrong. George is so busy programming, it's hard for him to find time to fix the Help file!) 

There are 6  basic steps in getting AGWPE and your sound card to handle packet. These steps are discussed in 6 different sections on this site:

1. Build or buy a radio-to-soundcard interface -- one wire each for RX, TX, and PTT.
2. Install and configure the AGWPE program.
3. Configure your sound card's settings
4. Configure Windows
5. Setup client applications to work with AGWPE
6. Troubleshoot problems - but hopefully this won't be necessary.

If you get hung up, you can e-mail me, KC2RLM. I'll try to answer your questions, but I won't pretend to be the complete AGWPE sound card expert. I am more of a technical writer than a technician. In fact, if you find any errors or omissions on these pages, please let me know.  For the best troubleshooting help, I suggest you subscribe to a special AGWPE Yahoo Group email list to ask for help from other AGWPE users and even the author, George, SV2AGW. 

Download This Web Site in PDF files  (English Only ... sorry )

You can get all the pages of this "Sound Card Packet" web site in an Adobe Acrobat PDF file. Go to the PDF File List page to select what you need.

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