Re: PI TNC - progress report.

John G8BPQ


I'm discussing with the maker of the TNC-X the possibility of him making and selling the boards. If that doesn't come off, I'll at least make the PCB and software availabale, so you can build your own.

73, John

--- In, ve2hom Pascal <ve2hom@...> wrote:

Hi John,
This sound very cool, give us news about your project. Do you plan
to make these board available to sell ?

73 de Pascal

Le 20/09/12 16:27, John Wiseman a écrit :

For those fairly new to the group, I have been working on a TNC for
use with the pI that is the same size as the pi and plugs into the
expansion header. The prototype was a TNC-X, with a 26 way header
superglued to board. There is a photo of it on the home page of this
I've now received the first PCB's, and built a couple. There are
photos at and The TNC is largely
based on the TNC-X, but I've replaced the serial port with an i2c
connection, so more than one can be connected to the PI. The current
board has a mini-DIN radio connector, but I find mini-DIN plugs very
difficult to wire, and the connector is just too high to stack
properly, so the final version will probably have a DB9. I've written
a linux driver that takes the i2c data stream, and converts to a pty
that can be used with the normal linux ax.25 kissattach program. All
this seems to be working.
I've a couple of developments in the pipeline. One is to replace the
MX 614 modem, hopefully with a PIC based solution. Although the 614
works very well, it is relatively exensive, and only works at 1200
baud. I hope to be able to run at 300 for HF use. I've also bought a
couple of RFM22B modules. These are tiny 100 mW 434MHz data
tranceivers - see I plan
to do a version of the TNC using this module.
A version using the FX 489 modem for 9600 baud links is planned, nut I
haven't started work on that yet.
73, John G8BPQ

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