From: auj@aber.ac.uk (Alun Jones)
Newsgroups: rec.radio.amateur.packet
Subject: AX25 protocol (Summary)
Summary: Thanks!
Date: 16 Nov 92 18:43:09 GMT
Organization: Prifysgol Cymru (University of Wales) Aberystwyth

Two weeks ago I asked the following:

> Sorry if this is an FAQ, I don't read this group regularly.
> 
> I am interested in building a simple packet modem and writing all the
> AX25 software necessary to get going on packet on my computer (Acorn
> A3000). Looking around the ftp sites (and on archie) I have totally 
> failed to find a description of the protocol. I am a total novice, not
> even knowing what audio frequencies are used, which makes it slightly
> difficult for be to get started!
> 
> Could someone please point me to an on-line description of the protocol,
> or a good book describing it.
> 
> Please reply via email, and I'll summarise to the group.
> 
> Alun.
> 
> p.s. I have looked on the buffalo ftp site but couldn't find it there...

I have received replies from the following people (in no particular order)

G|ran Bostr|m		Goran.Bostrom@se.infovox 
Ted Cline		tcline%com.hp.lvld.hplvec@uk.co.hewlett-packard.hpl
Pat Masterson		bat@com.grumman.gdstech 
Jon Vander Hill		jcv26@org.cas 
Bradley T Banko		btbg1194@edu.uiuc.cso.uxa
Adrian Godwin		agodwin@uk.co.acorn
Kevin Purcell		a-kevinp@com.microsoft
A.R.Bateman		cs9h0arb@uk.ac.swan.pyr

The following sent me copies of AX25.DOC, which as Ted Cline noted is
available by mailing him directly:
Ted Cline		tcline%com.hp.lvld.hplvec@uk.co.hewlett-packard.hpl
Pat Masterson		bat@com.grumman.gdstech 
G|ran Bostr|m		Goran.Bostrom@se.infovox 
Jon Vander Hill		jcv26@org.cas 

-----

Bradley T Banko (btbg1194@edu.uiuc.cso.uxa) suggested:
You might just dig up the sources to the Poor Man's Packet computer TNC
with modem (available around the net "archie pmp")... it includes some
pretty well documented C source subroutine files for AX.25.

-----

Adrian Godwin (agodwin@uk.co.acorn) pointed out that the NET package
has already been ported to Acorn's RISC OS machines, requiring a KISS
modem and not much else. He also suggested looking at pmp, and suggested
looking on ucsd.edu for KA9Q stuff.

-----

Kevin Purcell  (a-kevinp@com.microsoft) suggested:
You can find find all you need to know in a booklet published by the
ARRL called "AX25 Link layer protocol specification revision 4". I have
a copy at home but can't remeber the title exactly.

You should be able to buy this from folks who sell ARRL books (like the RSGB).

Its very dry reading (like all good specs) and provides a description
of a state machine which defines the protocol, so it shouldn't be too
difficult to implement directly.

-----

A.R.Bateman (cs9h0arb@uk.ac.swan.pyr) suggested:

I'm not sure about an on-line source for the AX.25 protocol, but the reference
I got was from the RSGB. It is a reproduction of the full protocol specification
document and was about 5 pounds I think.

-----

In view of the above I have decided to follow two courses in parallel.

Firstly I am trying to use AX25.DOC and the PMP sources to write a 
quick and dirty packet implementation based on the Baycom board design.
(Don't hold your breath, all you Acorn users - I have a lot on my plate!)

Secondly the KISS modem sounds like a more sensible idea, as I didn't 
realise how stringent the real-time constraints will be generating the
HDLC directly from software. Besides bit-stuffing is boring ;-)

Thanks to all who replied, all your help has been greatly useful.

Alun.

p.s. I've re-started reading this group now...
-- 
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| Alun Jones, Computer Science Dept. | Email : auj@uk.ac.aber       |
| U.W. Aberystwyth, Wales            | GW1URF (Packet coming soon!) |
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