Interface cable for Icom IC-7100 to a PK-232 Packet TNC

I was trying to interface the Icom IC-7100 to a PK-232 MBX Terminal Node Controller (TNC).  On my Yaesu radios it is a pretty simple matter to put a 6 pin mini DIN connector on the end of the PK-232 cable and have everything working in a very short time.  However, it wasn’t that easy on the IC-7100.  The IC-7100 is a great little radio, covers just about DC to daylight in a very compact package.  But I wanted to have the ability to use it on VHF packet radio, so interfacing the PK-232 was a requirement.

After trying the data port and the accessory port I realized what the problem was. There was no squelch on the audio from these two outputs. I found that information on using this new radio with a vintage TNC was very hard to find. Reading the manuals supplied with the transceiver didn’t help much.  After some additional investigation I saw that audio output from the receiver was available at the mic jack I then knew how to make the cable.  Since that was from the speaker it would be squelched.

Here is the connections to operate the PK-232 Terminal Node Controller with a Icom 7100 all mode all band radio.  Below is the cable details for creating your own interface cable.   On the left is the rear view of the RJ45 microphone connector on the IC-7100 matched up to the wire colors of a “standard” PK-232 radio cable as supplied by Timewave.  If you are using a Kantronics TNC look up the pin outs for it’s connector in the manual or on the web.  It should work just as well, although I don’t have a Kantronics TNC to test here.  If anyone out there tries the Kantronics drop me a note and let me know how it worked.

Click on image to expand

To enable the audio output to the microphone jack, you need to turn on “Speaker Out” in the function menu.   Press <SET> then select <Function> on the main menu, then scroll down to <Speaker Out> and set that on “ON.”

Set Speaker Out ON in the Function Menu

3 Comments so far

  1. Oliver Dully on January 9th, 2019

    Nice blog, I really like your IC-7100 coverage!

    Just by the way of a quick comment: Packet on VHF works extremely well with the built-in soundcard, CAT7200 by John Wiseman and Soundmodem100 (or Direwolf) on the IC-7100. That is one of the ways I do Winlink on a regular basis.

    Oliver K6OLI

  2. admin on May 25th, 2019

    Yes, I have tried that too. It works, but to me is a bit unstable. Everything has to be installed and started in the correct order or it is a no-go. Some of the guys in my club were tying to get their TNCs to work with the 7100 so I thought I would give it a try. It was harder than I though. My everyday packet station is an old Kenwood 50 watt 2 meter FM radio and a PK-232. I’ve been around long enough that I remember when the PK-232 originally came out on the market!

    DE N4RFC – Bob

  3. Frank Harris on April 19th, 2020

    Timewave makes cables for the 7300 they may also make one for the 7100. I talked with them this week. If you are looking for a terminal
    program they recommend Tera Term.