Dire Wolf is a software "soundcard" modem/TNC and APRS encoder/decoder.
It can be used stand-alone to observe APRS traffic, as a digipeater,
APRStt gateway, or Internet Gateway (IGate).  It can also be used as a
virtual TNC for other applications such as APRSIS32, UI-View32, Xastir,
APRS-TW, YAAC, UISS, Linux AX25, SARTrack, RMS Express, BPQ32, Outpost
PM, and many others.