Monday, October 22, 2012

Hints on connecting and debugging your ICOM M802 to a computer

Am still stepping through the SSB installation in Viking Star.  One of the things I have found out is Simple Directions DO NOT EXIST!  I also found out that the cable / DIN connecting that came with my Pactor modem was in poor condition and ended up bridging Vbat to the Trans pin.  Will, this blew a $0.23 FET IC inside the Pactor – as a result the whole digital HF communication aspect of this instalation is on hold until I get up enough stuff to make a order.    But till then, here are a few ‘hints’ I dug out when connecting the Computer to the SSB.

First off, why would one want to do this?  A couple of reasons:  Using Sailmail or similar product to send/receive Emails via SSB.  Another common reason is to allow for some level of automation when receiving weather FAX’s over HF.  How to do all this is another topic, for now I want to focus on a very small part of the overall system:  Connecting your Computer to the ICOM-M802 via RS-232 serial cable.

There are actually a couple of ways to let a computer control the ICOM:  Directly from the computer via an RS-232 cable, or indirectly through a Pactor modem, assuming you have one.  I chose to directly connect for three reasons:

  1. Our navigation computer has LOTS of serial ports. (By choice! - see Hardware for a Navigation computer).
  2. Some programs  (ala Ham Radio Integrator) cannot communicate through a Pactor modem.
  3. My Pactor modem is not one of the fancy ones with a second serial port – so it would not happen anyway.

OK, enough.  Here are some hints:

  • The serial cable only needs to carry TX and RX, plus GND.  Note that the ICOM instruction manual is a little confusing (err, more like wrong - they have RX and TX backwards) on this.  You only need a standard 9-pin serial connector – pins 2,3 and 5.  And more to the point, there is no need to bring forward things like DTR (Pin 4), DSR (6), etc.  So don't worry about them.  Just bring down 2,3 and 5 and get on with life.

  • Configuring the ICOM M802.  Refering to the users guide - Section 12 (SET MODE), page 48 in my copy.  You want to verify / change the following settings:

                      REMOTE IF  = NMEA (the ICOM communicates using NMEA sentences!)
                      REMOTE ID = 08
                      REMOTE MOD = ACC  (Most Pactor modems use the round ACC plug)
                      AUTO TUNE = ON
                      ICOM TUNER = Pick the one you are using

Those last three are really general settings and not needed to communicate with the computer.  But as long as you are in there!

  • Configure your serial port Port Settings (Control Panel / System / Device Manager / COM _ _):

                 Bits per second:  4800
                 Data Bits: 8
                 Parity:      None
                 Stop Bits: 1
                 Flow Control:  None

That is it!  Install the program of your choice and all will be well - - - unless it is not.  If things do NOT work you need to debug a little.  Here is where I had a bit of a struggle – trying to learn the system, debugging it, and using ‘complex’ control programs all at the same time.  One thing that was VERY helpful was being able to send and receive a simple test commands to  the radio and look for its reply - without a complex control program.

Under Windows go to Start / All Programs /  Accessories / Communication  and click on:  Hyper Terminal.  This will bring up the simple serial communication window.

  • Type ‘ICOM M802’ in the Name Window, and press OK.
  • On the next screen, change the last pull-down ‘Connect using’ to the serial port your radio is wired to.  In my case COM4 is the one.  Press OK
  • This next screen is the Port Settings – it should agree with what you did above.  Press OK.
  • Still a bit more to do.  Select File/Properties.  Choose the Settings Tab and click on the ASCII Setup.. button.  Check the ‘Send Line Ends with Line Feeds’  and the ‘Echo typed characters locally’ boxes.  
  • Press OK’s until you are back at the main com window.  
  • Type the following simple NMEA sentence:  $PICOA,90,08,REMOTE*7D and hit Enter.

If all is well, the radio will respond with something like $PICOA,08,90,REMOTE,OFF*42   It might end a little different, like , ON*50 - but never mind, the key here is:  Did you send a command to the radio, and did it reply.

And there you go.  If this simple test works your communication path between the computer and the ICOM-M802 works.  If the above does not work, double check the above steps.  But at least here is a simple test environment!


  1. Hi
    Thanks for the great article.
    Do you know where I can find a full set of NMEA Commands to control the ICOM 802M HF radio?

    1. If you send the command $PICOA,90,08,ALL*38 you will get the M802 to respond with everything it knows about. From the reply, you can pretty easily guess what individual sentences can be used to query or set radio parameters. The sentences will be something like:



    2. Paul, THANKS! This looks very interesting and I will need to see what my Radio has to say.

  2. Good and clear explanation
    Thanks for share


    1. You are welcome - while getting mine setup I always was wondering if the problem was the actually connection, or if I just did not know how to use the fully integrated communications software. . . Doing the above, I could proof the connection and then knew I needed to learn more about the integrated software.

  3. Is the serial cable a null-modem cable with pins 2-3, 3-2, and 5-5 or a straight through cable with pins 2-2, 3-3, and 5-5? Thanks, Don

    1. Hello. I can see from my text above it is perhaps not THAT clear. So, between my ICOM802 and the DB9 connector on the back of my computer I connected it as a straight-though cable, like this:

      2 <--> 2
      3 <--> 3
      5 <--> 5

      Hope this helps!

  4. This comment has been removed by the author.

  5. Hi,

    I've have a NMEA checksum generator if anyone needs it. I works on Windows currently. Also, I'm in the middle of writing a simple rig control program for the m802 so if you would like to test it out just let me know...

    Thank you,

    1. W0PRH - hey, thanks for sharing! Sure, if you want drop me a link to a copy. I need to do some debugging, as I am getting raised SWR ratios as of late. But maybe over the next couple of months will have time to play.

      -al- KF7HMU

    2. howdy,

      Created a yahoo group, its the only file. Should be working on the rig control in a week or so. The calc runs on Windows, and needs .NET framework 4.5. I can dumb down the .NET framework so if you have issues let me know.

      Just one note on the rig control I have the screen and command arrays completed just need to nail it up to the 802. Shouldn't be a biggie as I use the same basic gizmo on 6 other HF rigs. Usually only needs a tweak or two...


    3. Did you ever make progress on this? I'm trying to fix the hamlib icm802 entry which doesn't work right now.
      de Mike W9MDB

    4. Hello. I use the command connection as part of the WinLink software package running on Windows and connected via a USB -- RS232 dongle. It is able to take control of the M802 and change frequencies under computer control. But I have not done anything past that. Not sure if this helps you or not...