Sound Card Packet

Translations of this site

by  Ralph Milnes, NM5RM
last updated: 08/21/2011 What's new on the site?

Most recent AGWPE version is:

 2010.806  5 Aug 2010


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
    USB SignaLink
6. Using AGWPE
    AGWPE on a Network
Baud Rates & Modes
    Remote Control
    TCP/IP Over Radio
Tips and Tricks
Traffic Parameters
7. Compatible Programs:
    Setup Help
8. Packet Reference
    Exchange Modes
    Frame Headers
    TNCs and AGWPE
    What to do with Packet
    Common Frequencies
    Sound Card Mechanics
    Further Reading     



This amateur radio web site explains how to use the AGWPE utility program to send and receive packet -- a digital data mode -- using the sound card or sound chip of your PC instead of a traditional TNC or radio modem. (TNC = Terminal Node Controller, a hardware device that encodes and decodes packet data on radio signals.)

The site offers:

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

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

  • troubleshooting advice

Advantages and Limitations

Feature Highlights
Hardware requirements
Setup Steps

Packet Engine Pro
Notes about Vista or Windows 7 and AGWPE


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

Advantages of AGWPE:  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, 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.

Limitations: To be fair, other users claim they get better results with a TNC and that TNCs are easier to setup and much less likely to get mis-configured. TNCs also have:

  •  a built-in digipeater function, although you can run a separate digipeater program under AGWPE
  •  a mailbox system, although there are separate BBS programs that can link to AGWPEl
  •  a built-in "watch dog" timers  to prevent continuous transmitting in the event of an error, although you can add a watch-dog timer circuit to your AGWPE interface.

Also, not all computer sound cards/chips will work satisfactorily with AGWPE.

Please note that many 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 directly with AGWPE, but there are several good ones. In addition, Tim Pearson KB9VQF has written a AGWPE Serial Loopback utility that creates virtual serial ports that will let you link AGWPE to any packet program that can link to a KISS-enabled TNC (AGWPE's sound card mode simulates a KISS TNC).

Hardware Requirements:

  •  Operating System: The latest version of AGWPE runs most reliably on Windows XP. It may also run on Vista and Windows 7,  but some users have reported problems that haven't been resolved as of July 2010 (see this page).

    An older version (2005.127) of AGWPE should run on Windows  98, ME and 2000; versions newer than this will probably not work. Some users have been able to run the older version on NT 4.0 and Windows 95, but Win95 has been a problem for the program author.

    AGWPE will not run in plain old DOS or Windows 3.1. It also will not run directly on a Mac or on Linux, but it will run under a Windows emulator. (There is a product similar to AGWPE for Linux called LDSPED.)
  • Sound Card: AGWPE' s sound card packet mode should work with most recent vintage (2005 or later) 8-bit or higher sound cards and integrated main board sound chips. Earlier cards may not work. Note that most internal computer sound cards are inexpensive parts that are prone to sampling rate errors and electro-magnetic noise from other computer parts, and that may render them unsatisfactory for AGWPE use. Also, you may encounter a bug in configuring problems with newer High Definition cards.  Regardless of its age, you should also have the most up-to-date drivers for your sound card. For more information about sound cards, see this page.
  • Processor/CPU: Generally, any recent  vintage (2005 or later) processor will work just fine with AGWPE. Older Pentium II processors -- and anything newer -- should work. Some users have even used it on a 486, but other users have found it will not run satisfactorily on a Pentium I without MMX. (See More About AGWPE for more information about processor requirements.)

Feature Highlights: The sound card option in  AGWPE will allow you to:

  • Use "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.)
  • Use 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.
  • Install additional sound cards that can be used exclusively for sound card packet. Your first sound card can then be used by Windows and  other sound-producing programs and devices, such as your CD player.
  • Use a Sound Card Tuning Aid feature for accurately tuning signals, particularly on HF, and for setting the correct RX (receive) audio volume.
  • Access AGWPE on a remote computer over a home network or even the internet!

Setup Steps:  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 out of date and in some cases it is wrong.)

There are 4 basic steps in getting AGWPE and your sound card to handle packet. These steps are discussed in different sections on this site (see the top left margin of this page):

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 mixer (audio) settings in Windows
4. Configure Windows to allow TCP/IP use, if necessary,

In addition, there are three other sections that may prove helpful:
5. Troubleshooting problems
6. Using advanced AGWPE features

Setting up client applications to work with AGWPE

If you get hung up, you can e-mail me, NM5RM. 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. 

Packet Engine Pro: In 2003, George SV2AGW released a more advanced program, Packet Engine Pro, based on his original, freeware AGWPE program. The 'Pro' version:
  • runs more efficiently
  • has an improved interface
  • has a setup 'Wizard' that simplifies new sound card (and TNC) configurations
  • has 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 older Win95/98/ME systems):

  • PTT can be controlled with the parallel port in addition to the serial port
  • YAM modems
  • BayCom/BayPac modems, but only if your computer has legacy serial ports, i.e. non-ACPI  compliant serial ports ( ACPI is a power management/saving protocol)

Feature comparison chart for PE Pro and AGWPE

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

I encourage you to consider the Pro version because:

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

You can download the Pro version from the AGW Programs page

This web site provides support for the freeware version, AGWPE, but aspects of it may also be helpful for Pro users.

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