In article ,
Ian wrote:
I'm part of a student team working on developing AX.25 code
for an amature satellite application. We have been considering
both versions 2.0 and 2.2 but are not clear on the differences
between the two, if any. Does anyone have a good enough
understanding to explain them to me? Thank you.

One answer is that 2.0 was implemented and used, while 2.2 by and
large was neither implemented or used.

In this day and age, you might consider simply using IP for
satellite communications. A good place to start might be:

http://ipinspace.gsfc.nasa.gov/

-tjs