Dire Wolf
From APRSWiki
Dire Wolf is a software modem and APRS encoder/decoder. It can be used stand-alone to receive APRS messages or as a digipeater. It can also be used as a virtual TNC for other applications such as APRSIS32, UI-View32, Xastir, and many others. Both KISS and AGWPE protocols are supported for use by applications.
Links
- [1] - Details and download.