This is the contens of AX25_MAC.txt as it comes with AX25_MAC in the distribution.
The AX.25 Medium Access Control Layer Version 0.08 (25 January 2003) for DIGI_NED
Resident AX.25-driver for the PC and BayCom-Modem, SCC-Boards, PAR96, YAM96, PA0HZP-OptoPcScc Board, KISS, THD7/TMD700/TS2000, and DRSI cards, BPQ Ethernet by Henk de Groot, PE1DNN
Based on TFPCX 2.73 by Henk de Groot, PE1DNN Based on TFPCX 2.21 by René Stange, DG0FT
In 1997 DG0FT published his TFPCX work under the GNU General Public License, and stopped maintaining the code. I took over this code and implemented the latest firmware from NORD> When I needed a driver to send and receive raw AX.25 frames I looked at TFPCX. I only needed the MAC layer (Medium Access Control layer) part and not the NORD> Note that I can not guarantee that AX25-MAC will run without any problem on every PC when using a serial modem: especially when using a PC with a slow CPU you may encounter problems during reception. XTs running with a clock frequency below 8MHZ are not usable (or with limitations). Some TSR's (Terminate and Stay Resident) programs are known to cause problems (See Appendix 1.1.). Since this is not a commercial product I take this for granted. I think this program will work for most users with some compromises .
I like to thank René (DG0FT) for making all this software and making it available under the GPL license so I could reuse it.