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Introduction
Overview
Computer requirements
Packet Engine Pro
Configure AGWPE
Download and Install
Basic AGWPE Setup
2 Radio Setup
2 Card Setup
Sound Device Setup
Basic Device Settings
Rename Sound Device
Additional Settings
Using the Tuning Aid
Problems?
Program Behavior
Receiving
Transmitting
Connections
Firewalls
AGWPE Features
AGWPE on a Network
Baud Rates & Modes
Remote Control
TCP/IP Over Radio
Tips and Tricks
Traffic Parameters
Compatible Programs:
Setup Help
Radio Interface
Getting Started
Kits and Pre-assembled
USB SignaLink
Receive Audio Cable
Transmit Audio Cable
PTT (TX Control) Cable
2 Radio Modification
About Packet
Packet Overview
Exchange Modes
TNCs and AGWPE
What
To Do with Packet
Common Frequencies
Frame Headers
Further Reading
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AGWPE Overview
What AGWPE Does
History
Advantages and Limitations
Important Features
Basic Setup Steps
The AGWPE program has many features, but its sound card features
allow it to simulate a TNC. AGWPE was written so that other packet
programs (clients) can link to AGWPE and use AGWPE as a host that will
send and received packets for them. Call them AGWPE-compatible programs.
In fact, most popular packet programs -- APRS, BBS, terminal and WinLink
programs -- now have a way to link to AGWPE.
To run packet by sound card, you need:
- AGWPE
- an AGWPE-compatible program(s)
- an "interface" to connect your computer sound card to a radio
(in its simplest form an interface is three wire cables, two with
simple circuitry)
This website provides information about obtaining and configuring
those three components.
AGWPE was written by George Rossopoulos SV2AGW in the 1990s. AGWPE is
an acronym for "SV2AGW's
Packet Engine". It did not have sound card
packet features at first. It was originally designed as TNC management
utility and still has many super features of value to TNC users. For example,
AGWPE makes it possible for TNCs to connect to more than one
packet program at a time (TNCs can't do that without AGWPE) or have
programs connect to more than one TNC at a time (programs typically
couldn't do that without AGWPE).
AGWPE performs its magic with a TNC by placing the TNC in KISS mode
and then taking over responsibility for handling most of the logic
functions built into the TNC. The TNC is left to handle just packet tone
modulation/demodulation, or modem, functions. AGWPE handles the AX.25
protocol for connections and automatic repeat request for lost/damage
packets. In addition, AGWPE provides dynamic re-setting of packet timing
settings based on frequency traffic load, something TNCs do not do.
AGWPE was also designed to work with radio modems, such as the YAM
and BayCom. Radio modems can do the tone modulation/demodulation, but do
not have any of the logic functions built into TNCs. Instead, AGWPE
provides the TNC logic functions for those devices, as well.
In time, the program author, George SV2AGW, realized that a computer
sound card could emulate all the functions of a radio modem. So with the
TNC logic already in AGWPE and new code to use sound cards as a radio
modem, AGWPE was then able to simulate a TNC -- and Sound Card Packet
was born in the late 1990s!
Remember, for AGWPE to act as a host for other packet programs, or
clients, those programs must be written to link to AGWPE. Not all packet
programs can do this, but many can. Client program authors have gladly
added this option to their programs because AGWPE relieves them of the
need to write all the programming code that would be needed to control
different TNCs, radio modems, and Multi-mode Controllers. It's much
easier to let AGWPE do it! (Multi-mode controllers can run packet
plus some other digital modes, typically RTTY, AMTOR and PACTOR I.)
Client programs can link to AGWPE in one of two ways. The best way is
using the Windows TCP/IP Socket interface. (If you are a program author,
see open development
information). The other was is using an older, less capable
protocol, the Windows DDE (Dynamic Data Exchange) Manager, which only a
few older programs use.
Note that when a client program is using AGWPE as a host, any
settings in the client to control a TNC are no longer functional.
Instead, AGWPE controls the TNC.
Advantages and Limitations 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. The cheapest
TNCs 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 does not require a 12 V power source
as a TNC does.
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 with S3
or less signal strength; and the 9600 baud modem is better than the
original G3RUH modem.
Limitations: To be fair, some users claim they still 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 with AGWPE)
- a mailbox system (although there are separate
BBS programs that can link to AGWPE)
- 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)
- the ability to run without a computer (for digipeating,
beaconing)
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 (cost $25) that creates virtual serial ports that
will let you link AGWPE to ANY packet program that can link to a
KISS-enabled TNC.
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!
Basic Setup Steps
Getting AGWPE to work correctly can be tricky, since you will need
the radio-to-computer interface, 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):
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