Bob Schreibmaier k2ph at dxis.monroe.pa.us
Sun Aug 22 08:36:28 EDT 1993

I was going to just send this only to Ken, but thought it might be
useful to others as well.

I once wrote a short article for the Frankford Radio Club newsletter
on a device that would control a IC-765.  It uses half of a 4011 quad
NAND gate IC (connected as inverters), one 5.1-volt Zener diode and a
1N914/1N4148 diode.  It's tough to draw the schematic in ASCII, so
I'll try to describe it in words.

Connect two of the NAND gates as inverters by connecting both inputs
together.  Then, take one of the inputs and connect it to the transmit
data lead on the RS-232 interface.  Connect the output of the other
inverter to the receive data lead on the RS-232 interface.  Connect
the unused ends of the inverters to a 5.1-volt Zener diode.  The
other end of the Zener diode goes to ground.  Take the junction of
the Zener diode with the two inverters and connect this to the Icom.
Oh yes, connect the 1N914/1N4148 diode from the Data Terminal Ready
lead on the RS-232 interface to the + power lead on the 4011.  K1EA
was thoughtful enough to turn this lead high while CT is running.
This way, the converter is powered by the PC.  By the way, you can
build the whole thing around a 14-pin DIP socket and fit it all
inside a DB-25 hood if you know how to cram things in.  :-)

I called this the "GYT Special ICOM Interface."

I hope this description helps.

Bob K2PH

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