[ICOM] Question about the CT-17 Level Converter

[Dave Bernstein]

Besides purchasing an expensive new CT-17 or locating a cheaper used
one, you have three choices: 

1. buy a 3rd party converter for $25 to $100:
     
http://k1nu.home.comcast.net/k1nu/Products/ 

http://www.cssincorp.com/prod-cable.htm 

http://home.att.net/~n8st/icom.html 

http://www.microham.com/USB%20interfaces.html 

http://home.comcast.net/~n4vas/wsb/html/view.cgi-home.html-.html

http://n9zle.tripod.com/cable.htm   (warning -- this is a tripod-hosted
site; don't go here without a firewall!)

http://hosenose.com/detail.asp?product_id=LCU-3  (by W1GEE -- recent
traffic indicates problems when used with IC765 or IC781)

http://members.fortunecity.com/w2eny/civ/ (expensive, currently out of
stock, web site attempts to download spyware)

You'll find reviews of the above products at
http://www.eham.net/reviews/products/53


2. Build one yourself

This is a fun project you can do for less than $10 if you don't get too
fancy with the packaging. Radio Shack has everything you need, as does
Digikey and other mail order houses. The circuit I use was published by
Nigel KG7SG in the 7/92 QST, and can be found in
http://www.qsl.net/civ_commander/interface.jpg ; like many others, it
derives its power from the serial port's modem control signals DTR and
RTS. This is fine, as long as you configure whatever software you're
using to assert these signals. Alternatively, you can power the circuit
from an external source of +12VDC. Ekki DF4OR has this and some other
circuits on his site at http://www.plicht.de/ekki/civ/civ-p2.html , but
I'd stay away from anything that directly drives the CI-V bus with a
MAX232 level converter; its output does not conform to the CI-V bus spec
-- though Icom itself uses this design in the CT-17. An excellent
example of a MAX232-based design done correctly can be found in
http://www.seed-solutions.com/gregordy/Amateur%20Radio/Experimentation/C
IVInterface.htm .


3. Convert your FIF-232C

Both Icom and Kenwood use TTL levels, but Icom uses a single-wire bus
arrangement to which multiple transceivers can be attached. To convert
your FIF-232C for use with the CI-V bus, you'll need to interpose an
open-collector TTL gate (e.g. one section of a 7407 hex buffer/driver)
between the FIF-232C's TTL output and the CI-V bus; the CI-V bus is
directly connected to the FIF-232C's TTL input. Were I doing this, I'd
mount a .125" female phone jack in the FIF-232C for the CI-V bus,
leaving the Kenwood wiring intact on its DIN radio port. Then you can
use an off-the-shelf moulded .125" male-to-male cable to connect the
FIF-232C to your Icom tranceiver's CI-V connector. Assuming the
FIF-232C's internal power supply produces the +5VDC needed for the
7407's Vcc, your cost is limited to one 7407 and one mini phone jack;
thus this is probably your least expensive option.


When you get around to considering software, take a look at DXLab. Its
completely free, and available via www.qsl.net/dxlab .

      73,

           Dave, AA6YQ


-----Original Message-----
From: icom-bounces at mailman.qth.net [mailto:icom-bounces at mailman.qth.net]
On Behalf Of Bob Scott
Sent: Friday, June 04, 2004 08:28
To: icom at mailman.qth.net
Subject: [ICOM] Question about the CT-17 Level Converter


I am thinking of purchasing an Icom IC-756-PRO II and want to control it
via computer.  I believe that requires me to get the CT-17.  Is that
correct? Is this the only option if I wish to computer control the
transeiver.  I have a Yaesu level converter, a FIF-232C that I need to
dig out, but I would be surprised if it did the same thing.  My
FT-1000MP Mark V Field has a build in 232 port, so it has not been an
issue before.  Any advice/guidance is welcomed. Thanks and 73,

Bob
W4ZY

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