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Author Topic: Confused re: Icom 746pro link to PC  (Read 10287 times)

Posts: 142

« on: November 06, 2008, 10:03:40 AM »

I want to run Ham Radio Deluxe linked to my 746 Pro. I read the manual (big help), spoke to someone at a ham radio store, and read various web pages and links here on eham looking for exactly what I need and am confused.
My PC has both RS232 ports and USB ports. I would prefer to use the RS232 connection, since most of my USB ports are already taken.

The Icom manual lists several types of digital connections,but doesnt go into enough detail on which one to choose.
1. What cable interface attaches to the Icom end?
2. Is there a converter box needed or does a straight cable connection work?
3. Can someone post a link to the website that shows what I need?

Posts: 93

« Reply #1 on: November 06, 2008, 02:42:44 PM »

Check the HRD user site

This link will take you to the HRD interface document.
The CIV unit plugs into the back of the radio (3/8"plug) the other end is a rs-232 connection for the PC.  This will give you rig control.  

You can either build (I did) or buy the rig control interface.   Many hams use one of the Rigblaster or MFJ units.  Check the reviews on eham for other choices.

For PSK work you'll need to add a soundcard interface and  maybe an additional rs-232 connection for PTT.  

If you'd rather use USB connections, just add either an internal USB card or external USB hub to you PC.

I've had poor luck with serial to USB converters.  I finally added an internal dual rs232 card to my PC.

Posts: 142

« Reply #2 on: November 06, 2008, 04:46:44 PM »


After I posted this I came across a solution using the Radio Shack 20-047 USB scanner interface.
I figured it was worth a try and picked one up on the way home. After unplugging an inactive USB cable from one of my external HD to make room, I installed the cable and drivers, plugged it into the remote control jack in the back panel ( that is where I was confused - I originally thought I had to use the data port), clicked on HRD , which I had installed the night before, and .... it worked!!
Not too many things I can say work right from the start, but this does. I'm impressed. HRD is slick and seems very usable. I played with the band scope and then the DX cluster features for a while after dinner and think I will be staying up pretty late tonight ...!

Posts: 170


« Reply #3 on: December 21, 2008, 12:45:31 AM »

You can build a "CT-17" clone from the schematic for a whopping 15 bucks in parts from Mouser, it's only 1 IC, a MAX232, and a handful of resistors and caps, this is the Icom "4 radios to 1 PC" interface you will see in the back of your 746 manual under "accessories", a new one costs around 120 bucks and used they fetch 70-80 dollars!

Or you can build a single rig to PC cable from a number of schematics on the web for a few bucks,

I built a copy of the CT-17 and it works like a champ, it is a simple project and you will get a lot of satisfaction seeing it work!

Good luck

Bill K4FX

Posts: 1

« Reply #4 on: January 01, 2009, 04:23:14 PM »

I also just purchased the Radio Shack USB cable. Can you tell me if you did or did not need to use the adaptor that came with it? I am having problems getting it to communicate with my 746Pro.

This will help me trouble shoot further.




Posts: 388

« Reply #5 on: January 06, 2009, 10:54:11 AM »

I have two of the RS scanner interfaces in use with Ham Radio Deluxe.  On my IC-756PR03 and 746 Pro, I do not use the adapter.  I also run HRD with my IC-706MkIIG, which requires the adapter to be used.  For the 746Pro, you'll need to set the CI-V address in the radio to 66H (default) to match the HRD software.  In the 'Connect' dialog window, check the box for DTS and uncheck the RTS box.  Also, I did not use the CD that came with the interface cable.  The instructions warn you that you must not let Windows try to install it's own drivers...that you must use the ones provided on the disk.  Strange thing is that I plugged the cable in to the USB port, Windows recognized the new hardware and did its thing.  next thing I knew, I was connected to and able to control my rig without ever even taking the CD out of the package.  I'm running Windows XP and using HRD Version 4.1, build 2055.  

Posts: 1

« Reply #6 on: October 29, 2009, 05:22:57 AM »

I just got a CT-17 to interface my Dell D-620 laptop to my IC-746 Pro, i am having problems finding a DB-25 pin (male)to a DB-9 pin (female) in my area. Wondering if someone out there has one, I would like to buy one, or find somewhere to order one.  Also. wondering if I could us a USB to a DB-25 pin? I did find one of those.
But I have seen several post saying that the USB don't
work as Well.

If you can help, please email me at, and put CT-17 in the subject line, so it don't get deleted


Posts: 14492

« Reply #7 on: October 29, 2009, 11:04:04 AM »

There are two interfaces. One is the CI-V rig control interface. It is the 1/8-inch phone jack on the back of the radio. It transferrers data back and forth to do things like read or set dial frequencies, select filters, etc. It dozen't not transmit any data over the air. The signal at that jack is serial at a 0 and +5 volt levels. Computer serial ports are usually around +9V and -9V so you can't make a direct connection. You need an Icom CT-17 converter or an equivalent. As you apparently found, there are some new converters out that convert the 5V levels to USB and install virtual serial port drivers on the computer to make the converter look like a legacy RS-232 serial port for the software.

The other type of interface is the data mode interface (which is really mostly audio). It generally connects to the input/output of the computer sound card and makes audio connections to the receiver audio output and transmitter audio input. This can be via speaker/mike jack or the MOD and fixed output connections on the ACC connector on Icom radios. There are now some data interfaces around that contain their own built-in sound card and connect to the computer via a USB cable in lieu of using the computer's sound card. The still connect to the radio's audio input and output in some manner. Many data mode programs use the RTS or DTR pin on the RS-232 interface to control the transmitter's PTT via a switch often built into the sound card interface. A few programs can control PTT via the CI-V interface instead.

Bob  AA4PB
Garrisonville, VA
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