Hi David.
> So my understanding of AX.25 is as follows: The Linux Kernel
> gets a network packet all ready to go, but instead of launching
> it through it's network device (eth0 for example), using IP
> Masquerading and hard routing commands, I can get it to route
> the information through the serial port. At which time the kiss
> protocol is utilized as a driver so the kernel can send and
> receive packets through the serial port packet device. And
> isn't it true that the actual protocol of the packets exchanged
> is AX.25?
Perhaps the following URL will be of interest to you...
Q> http://www.tapr.org/tapr/pdf/AX25.2.2.pdf
...it is the current 2.2 specification of the AX.25 protocol in Adobe
Acrobat format. Be warned in advance that it's around 1.6M in size, so
don't try downloading it over a 1200 Baud link...
Alternatively, the following is the same document in HTML format...
Q> http://www.tapr.org/tapr/html/pubsf.html
...just choose whichever is easiest.
> The reason I need to know is because I would like this group of
> students to write a driver for windows 95/98 (maybe NT) to allow
> the same sort of device interaction. Naturally I'm looking for
> "double click the setup.exe" with minimal instructions. I'm a
> UNIX Admin / programmer by trade, but I also see the value in
> making this hobby easier for others, thereby growing the hobby.
> In my mind I envision Windows 95, and Linux chatting happily
> along using the same protocol Linux is currently using for AX.25.
I believe that has already been done - certainly, there's an MS-DOS
based implementation available at...
Q> ftp://ftp.hzeeland.nl/pub2/hamradio/funet/packet/g8bpq/
...and I believe Phil G8BPQ has written a Win9x based version of his
code as well.
> They also plan on building a radio card for a PC also. While I
> think this is over the scope of the class, and that it may be
> too expensive to actually distribute, the professor strongly
> disagrees with me, and insists that they can make it work. They
> feel they can manufacture enough to make them reasonably priced,
> but he also is willing to sell them in "kit" form, to be built
> by the end user. The kit's might cost $75.00. The goal of the
> group is to start at 9.6Kb, and then move up to 19.2.
>From a personal viewpoint, I would be interested, but would consider
$75 to be a little too high. If they can keep it under $60, then I
would certainly be interested.
> I should mention they want to use the 222MHz band. And then if
> all goes well, they would move right up to 56Kb.
If the board is only available for the 222MHz band then it will be of
no interest to me as that band doesn't exist here. However, a board
for the 70cm band (430-440MHz here in Scotland) would certainly be of
interest.
> I'm excited about the potential of this project, but I lack the
> understanding of the actual protocol, and of high-speed packet
> in general. I would greatly appreciate a critique of the
> proposed plan.
> Specific Questions
> 1) What is the actual protocol used in the packets via the radio link?
See the links above for the FULL specification.
> 2) Has anyone already created a driver for windows for this
> protocol?
Yes, G8BPQ created one back in 1996 if my memory's right, although I
can't find it on the Internet. However, if you have a look in most of
the 2.0 or later Linux kernel sources, you should find the following
file...
Q> linux/drivers/net/hamradio/bpqether.c
...which is a Linux driver that can talk across an ethernet link to a
G8BPQ node (DOS or Win9x).
> 3) Is it possible (with a driver, some convoluted way) to get
> windows to be compatible with the Linux AX.25 protocol? Has it
> been done before? Website?
Windows itself has little to do with the matter. If the driver talks
AX.25 to the radio link, then the operating system supports it.
> 4) If the above is over ambitious. What other protocols could be
> used which would be compatible for multiple operating systems?
The above may or may not be over-ambitious, depending on the skills of
the programmers and engineers concerned.
> 5) What piece of hardware (within the scope of this project) do you think
> the "global" amateur radio community would benefit most from?
Note that TCP/IP over AX>25 is already supported in Linux, and I
believe there are MS-DOS mode drivers that can do the same. However,
I'm not sure whether there are any Win9x drivers for doing that...
Best wishes from Riley.
PS: The kernel versions page is now back online at the URL below, and
includes separate sublists both for each kernel series, and for
each year of development.
+----------------------------------------------------------------------+
| There is something frustrating about the quality and speed of Linux |
| development, ie., the quality is too high and the speed is too high, |
| in other words, I can implement this XXXX feature, but I bet someone |
| else has already done so and is just about to release their patch. |
+----------------------------------------------------------------------+
* http://www.memalpha.cx/Linux/Kernel/
