[simpits-tech] my com stack

[Cris Harrison]

oh well have you fought will your control heads, and the crazy pin-outs?
well I started building my radio stack I found on eBay a Gables G-4390 
with a yellow tag! I paid about 30 bucks including shipping.  The bad 
news is the connectors is going to set me back another 100 bucks or more.
Onwards well this is what i found out the each of the 4 heads, 2 nav, 
and 2 com, have 5 pins per digit, this is the 2 of 5 code.

This is the article that I wrote:
http://simpits.wetpaint.com/page/2+of+5+Code
I am also putting this into the Wikipedia

The control head has 5 groups of 5 plus I added a status to monitor the 
on-off, and test switches,
so you need a bus with 6 groups of 5 data lines ( since most computers 
use 8 bits, just pull the 3 unused lines up. a great part for this is a 
74LS125 or 126 (quad bus buffers)  they have tri-state outputs.
you can select the output group with a  74LS138 (3 of 8) decoder and if 
you need more selects you can chain this part and its great for this 
application as it want low active inputs.

then do a little code to read and write your port. tada.

Enjoy
Cris H.
phoenixcomm.net/~phnx2000/sim
phoenixaerospace.us

more later