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Hi,

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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 group.

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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.

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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.

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A version using the FX 489 modem for 9600 baud links is planned, nut I haven't started work on that yet.

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73, John G8BPQ