Oops, Obviously the "X.25" should read "AX.25" And follow this link to the definition of V 2.2 of the spec: http://www.tapr.org/tapr/html/ax25.html. Tom On Saturday, March 21, 1998 12:15 PM, Tom Mariner [SMTP:Tom_Mariner@EMAIL.MSN.COM] wrote: > Hola Mark, > > Since tnc's talk X.25, I would start at > http://www.arrl.org/catalog/index.html, the catalog page of the Amateur > Radio Relay League. I would order the book Practical Packet Radio, by Stan > Horzepa. > We have done some applications in X.25 in parts from 16C54's to 16C74's and > they work great. The HDLC-style protocol is medium complex, but is designed > for networks that have RF as the physical layer. The code, however, belongs > to our clients and / or us. >