Besides using a TNC for a transmission speed of 9k6 bit/s, there is also the possibility to establish “slower” connections.
The data rate of 1k2 – as it is also used for APRS or data connections to the International Space Station ISS – has the attraction of being less demanding in terms of the quality of the radio transmission path. This refers not only to the signal-to-noise ratio, but also to the less complex hardware used. 1k2 works in the simplest case via the microphone or line-in input of the soundcard and its line-out connector.
In spring 2020 I installed the corresponding configuration with a Raspberry Pi 3, a sound interface SCU-17 from YAESU and a transceiver FT-897 from the same manufacturer.
My radio friend Anderl, DL9MDV, gave me the idea to use the software direwolf. This software provides a virtual TNC. Together with linpac, a terminal program under Linux, the access to the local repeater DB0AAT on the 70cm band works quite fast.
Here are some screenshots to give you an impression: