Hi all,

If anyone remembers, I recently finished my prototype PIC based IFR and
radio trainer for the aero club.

After using it for awhile, it has become "painfully" obvious that it's
present wiring layout needs improving. Although the project works quite
well with a central station feeding PC's in a star fashion using RS232,
the "pilots" end up sitting too close together. Spreading them out
further would involve stringing messy cables outward from the centre.

What I would like to do is have a pilot "station" located in each corner
of the average sized room that is used for training. (4 stations total)
These would each house a PIC (16F628) for control, seperate LM386
amplifiers for the headset, and PC serial port to RS485 circuitry and
power regs.

I was hoping a single cable connecting each station in a daisy chain
arrangement, would carry 12VDC for the amps and logic circuits, a pair
for the data link, and 2 pairs for the 2 audio busses. I imagine the
cable would have to have individually shielded wires. Perhaps 1
data/power cable and 1 twin shielded audio cable.

The PICs in this arrangement all listen on the data link and connect the
headsets to the appropriate audio bus when required.

I am not good at analog electronics and was wondering if anyone could
foresee problems on the audio side of this approach. Crosstalk, data
signal noise etc. I suppose there would be 15 - 20 meters of cable
around the room from the first station to the last.

regards

Tony

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