Xref: utzoo rec.ham-radio:12147 rec.ham-radio.packet:2327 sci.electronics:7164
Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!bbn!bbn.com!grossman
From: grossman@bbn.com (Martin Grossman)
Newsgroups: rec.ham-radio,rec.ham-radio.packet,sci.electronics
Subject: rs232 control for ICOM radios
Keywords: ICOM rs232
Message-ID: <43525@bbn.COM>
Date: 31 Jul 89 15:11:38 GMT
Sender: news@bbn.COM
Lines: 38

After reading article in August '89 "73 Amateur Radio" page 34
"Control Your Rig from a PC" my brother KA1PPG (without usenet access)
asked if its do-able on his rigs.  I've read both manuals on his
ICOM IC-740 and IC-251.  It seams not possible on the 740 since the
only leads that are come close are:

pin #		Description

11	Input for TRANSVERTER control.  When 8 Volts DC applied, the
	set can operate with a transverter.

12	Output reference voltage for band switching
13**	Output for external band switching

It seams do-able on his 251 because it has the following connections
on the ACC connector:

pin #		Description

16	Control signal (DBC) input terminal for external control
17	NC
18	NC
19	Control signal (DV) output terminal for external control
20	Control signal (RT) input terminal for external control
21	Data signal (DB1) input/output terminal for external control
22	Data signal (DB2) input/output terminal for external control
23	Data signal (DB4) input/output terminal for external control
24	Data signal (DB8) input/output terminal for external control


Now the article mentions that some radios have an input and output
that are 5V rs232 signals but neither of these do.

So can someone explain (or point me in the right direction) how to use
pins 16-24.

PS I can easily make my brother a board like mine that uses an 8255 PPI
   chip for digital control, if thats whats needed.