soundmodem provides an AX.25 interface through a sound card device, eliminating the need for a TNC.

Before it can be used, soundmodem must be configured by issuing the command: soundmodemconfig&. This will launch the configuration dialog.

Multiple configurations can be configured, the first step is to start a new configuration:

This will open a dialog requesting a name for the configuration:

Enter the appropriate data for your sound card. The lower part of the dialog is only applicable if hamlib is to be used. The Channel Access tab contains a few TNC parameters and generally the defaults should be used until more experience is gained with the particular channel:

After creating the configuration, it is now necessary to create a new channel:

The channel contains specifics about the modulation as well as identification. For the modulator, the values shown below are typical for VHF packet:

The demodulator will typically be set to the same values as the modulator:

the Packet I/O contains identification specific to your station. The Interface Name must match the name of port in /etc/ax25/axports (Figure 55, “/etc/ax25/axports”) if the ax25-apps (Section 6.2, “ax25-apps”) is to work properly. Similarly, the Callsign, which should contain your station's SSID, must also match the value in axports. The IP Address should be the address assigned by your local AMPRnet coordinator. The remaining fields have their typical meaning.

You must also set up /etc/ax25/axports to create a port for your sound device. (Refer to Section 6.1, “ax25-tools”.) You may now use the axlisten and axcall applications described in Section 6.2, “ax25-apps”. If you have IP resources available, you may also use ordinary network applications. soundmodemconfig provides basic routes, but depending on your local environment, you may wish to add additional routes.