Vintage Icom to

Ham Radio Deluxe

 Interface Project

 

This is the final step in the evolution of my vintage Icom interface project. The original was simply a one off implementation that only worked on my IC-720A which I own. After showing that on Youtube, many people wanted the same capability. I started providing the programmed processor for that original project, and later I provided the CAD files for a PCB. . I was subsequently asked if I could interface to other radios. I looked into this, and discovered that my original code and PCB could not simply be tweaked, but both needed a major overhaul to support all the radios that had pre-CI-V (AKA CAT CONTROL) capability. This is an understatement. Several of the radios use a protocol similar to the 720A, but the logic uses 9V levels instead of the 5V levels on the 720A. Three of the radios have a completely different protocol but use 5V. Then there is the IC-701 which actually requires an analog signal in addition to the digital circuitry. With these new changes, I had to retire the original code and PCB which is here for reference. The second iteration in this project accommodated the additional radios, and I provided the CAD files for a PCB for that which can be seen here. I made the PCB single sided for with through hole components for easy do it yourself construction. I was still getting requests for a PCB though, and I decided to make a commercially manufactured double sided PCB available. The code for this third version is identical and programmed chips from version 2 can be used on the version 3 PCB. In fact, the version 3 schematic is almost identical to the version 2 schematic except for the addition of a jumper to select between the USB connection and the RS-232 serial connection. The version 3 PCB uses Surface Mount parts, but don't worry, I used big 1206 components for simple DIY construction.

 

Icom used the same 24 pin Molex connector for the accessory jack on many radios from 1976 to the mid-1980s. I have chosen to support all of the radios that had a parallel data based non-CI-V interface. Supported radios and their I/O connections are shown below in Table 4. So far, I have tested this new design on a few radios, as shown in Table 4. You can see videos of these working on my YouTube channel at http://www.youtube.com/user/TinkTron.  I don’t possess the other radios. I am willing to make a deal with people that do have the other radios. I believe that I have written the code to work on all of the radios in Table 4, but I won’t claim it works until tested. If somebody is ever in my part of the world and has an unverified radio they would like to try, I will give them the chip for free if and when it works. I am not willing to take possession of radios thru mail or UPS. I don’t want the hassle of having something happen to the radio during transit. This must be done in person. I realize this might take a long time to finish.

 

In a nut shell, my code inside the microcontroller emulates an Icom IC-7000. Ham Radio Deluxe (HRD) believes that it is communicating with a ‘7000, and all of the data that it sends to the PIC microcontroller chip is then translated into commands that the vintage Icom radio understands to perform the same functions as commanded by HRD. All radios support the frequency control and PTT. The 720A also supports mode selection. The 720A was the only radio that provided remote control of mode selection. I have provided three methods to interface to HRD. A regular serial (RS-232) connection, USB, or the Icom CI-V interface are all supported. There is a jumper on the PCB provided to select between RS-232 and USB. The hardware can be installed for both, but only one can be used at any given time.

 

The schematic for the interface is shown below in Figure 1. The NAND gate is used to split the single wire CI-V signal into separate TX and RX signals. This was needed to make the signals compatible with the output of the RS-232 chip (IC1) as well as the USB chip (IC5).  Whatever communication method is used, the signals end up at pins 10 and 12 of the PIC (U1) as 5V serial signals. The I/O pins to the right of the PIC in the schematic all begin with the letter “M”. This denotes the pin number used on the 24 pin Molex connector. IC4 is an op amp that is used to provide the analog signal that is used only on the IC-701 for band switching. LED1 is mounted on the board and is an LED that is used for troubleshooting. It’s ON/OFF state toggles as packets are received from HRD. It is also used to verify configuration of the chip, which will be discussed below. R6 is used for a power indicator LED should the PCB be mounted in an enclosure. The board is powered by 12V that is supplied from the radio on pin “M2”. If it is desired to put a power switch on the interface, the 12V from “M2” should be interrupted with the switch. Q2 drives pin “M3” which is used for PTT.  Pads DB2, DB3, and DB5 correspond to the pins on a DB9F connector for use with RS-232. Pad CIV1 is the center connector and CIV2 is the shield on a 1/8 inch connector used on Icom CI-V interfaces. The USB Pads correspond to the 4 signals on a standard USB interface.

 

 

Figure 1. Schematic for the Vintage Icom to HRD interface

 

 

The top and bottom layers of the PCB are shown in Figure 2. All parts are surface mount except the processor, LED, 2 transistors, jumper block, and the diode. The processor is a DIP chip so that it can be reprogrammed if an important revision occurs. Larger SMD parts were used to make construction easier for the home builder, except the USB chip( IC5). This chip was only available in a smaller pitch package. All other components are 1206 packages or 50 mil spacing ICs. Because of the variety of radios supported, construction is not the same for all boards. Differences are outlined in Table 2. If using the USB chip, an associated driver is required for your Windows computer. Most newer operating systems will find the driver automatically. If yours does not, the driver is available from the FTDI website at http://www.ftdichip.com .

 

 

An IC socket is highly recommended for U1. I did not choose a USB connector because I wanted to leave that to the builder and their individual tastes. Whatever you use, make sure your USB connection are very short. Make certain that you get the MAX232A that uses .1 uF caps instead of the one that uses 1 uF caps. LED1 is an off board indicator that can be mounted on the face of whatever enclosure this board is mounted in. In all cases for IC placement, the reference designator on the PCB is on the side closest to pin 1 of the IC package. The jumper header SV1 can be eliminated and a hardwire implemented if only RS-232 or USB is used. The SV1 pads can be left open if only CI-V communication is used.

 

This is not a project for beginners and I will not hold your hand. Don’t take this on if you are a beginner at this sort of thing because my support will be minimal, if any. This project has turned into quite a time sink. Undertake this project at your own risk. Use common sense testing before you attach the finished project to your radio. The microprocessors used in these old radios are irreplaceable and I will not be responsible for your errors.

 

 

Part

Value

Package

Comment

Digikey P/N

 

 

 

 

 

C1,C4,C5,C6

.1uf

1206

 

399-1249-1-ND

C16

10 uF

1206

 

587-1352-1-ND

D3

1N4004

DO41-10

 

641-1311-1-ND

IC1

74HC00

SO14

 

568-10105-1-ND

IC2

78L05SMD

SO08

 

497-1180-1-ND

LED1

LED5MM

5mm

 

C566C-RFS-CT0W0BB2CT-ND

Q1,Q2

2N2222A

TO18

Almost any NPN will work. Observe pin out

2N2222ACS-ND

R1,R2,R4

10K

1206

 

P10.0KFCT-ND

R6,R8

470

1206

 

RMCF1206JT470RCT-ND

R12

22K

1206

 

P22KECT-ND

R7

2.2K

1206

 

RMCF1206JT2K20CT-ND

SV1

jumper header

.1" pitch

Hardwire if only using USB or RS-232 only

3M9448-ND

jumper

jumper

 

Hardwire if only using USB or RS-232 only

A26228-ND

U1

16F690

DIP20

Programmed IC available from KA6BFB for $35 plus shipping

N/A

PCB

 

 

Available from KA6BFB for $30 plus shipping

N/A

Molex Connector

 

 

 

WM1219-ND

Molex Pins

 

 

 

WM3680CT-ND

 

 

 

 

 

R5

100

1206

Populate only on IC-720A application

P100ECT-ND

 

 

 

 

 

IC4

MAX232A

SO16

Populate only when using RS-232

MAX232ACSE+-ND

C9,C10,C11,C12

.1uf

1206

Populate only when using RS-232

399-1249-1-ND

 

 

 

 

 

IC5

FT232RL

SSOP28

Populate only when using USB

768-1007-1-ND

C3,C13,C14

.1uf

1206

Populate only when using USB

399-1249-1-ND

C15

10 uF

1206

Populate only when using USB

587-1352-1-ND

 

 

 

 

 

R3,R9,R10,R11

2.7K

1206

Populate only on IC-701 application

RMCF1206JT2K70CT-ND

C2,C7,C8

.1uf

1206

Populate only on IC-701 application

399-1249-1-ND

IC3

LM358D

SO08

Populate only on IC-701 application

497-1591-1-ND

 

Table 2. Parts list for Vintage Icom to HRD Interface

 

 

 

 

Figure 2. Top and bottom layers of the  PCB.

 

 

Figure 3. Finished prototype interface used for validation.

 

 

 

As I mentioned earlier, there were different protocols required for different radios. In general, the pins on the accessory jack that are used for interfacing are 13,16,18-24. Table 3 is a compilation of the different functions and voltage levels for each pin as it applies to each radio. An “X” means the pin is not used. The individual signals are in quotes in the table and reflect the usage in the individual user and service manuals for the radios. For example. “RT” is used in the 720A and means “remote”, while “8” is used on several radios and reflects the binary 8 pin in a parallel bus. It is not required to understand the meaning of this table, it is just shown for those that might be interested

 

 

 

 

PIN

13

16

18

19

20

21

22

23

24

 

              RADIO

720

720A

X

 

I     “DBC”

 

5V

   I

“RC”

 5V

O     “DV”

 

5V

 

I      “RT”

 

5V

 

I/O     “1”

 

5V

 

I/O     “2”

 

5V

I/O     “4”

 

5V

I/O     “8”

 

5V

 

251,255,260

451,551,560

X

 

 

9V

X

 

 

9V

 

9V

 

9V

 

9V

 

9V

 

9V

 

701

   I

ANA

LOG

I

“UDC”

 

I

“CL”

 

  

     I

   “E”

     5V

 

      I

    “0”

     5V

 

      I

    “1”

     5V

 

      I

    “2”

     5V

 

      I

    “4”

     5V

 

      I

    “8”

     5V

 

211,245

X

 

I

“UDC” 

I

“CL”

Table 3. Pin functional list vs. Radio for the pins on the accessory jack.

 

 

 

DAUGHTER BOARD

 

NOTE: This daughterboard is only required for the radios as described in Table 3 as 9V radios and in Table 4 as radios that require level translation. All other radios connect directly to the main interface PCB.

 

For all the radios above that require 9V logic, I have made a bidirectional level translator board that goes between the interface board and the radio. This board converts all signals that are necessary to be converted from 5V to 9V. As shown in the table, this is needed for the 251,255,260,451,551 and 560. As of this writing, this board has been successfully tested on a 251, and therefore should work on all of them. The schematic for this translator board is shown in Figure 4 and the parts placement is shown in Figure 5. I have not made commercial PCBs for this yet, but I may in the future. 

 

Figure 5. Schematic for translator board

 

 

 

Description: C:\Users\Dave\Desktop\website\projects\Vintage Icom Interface_files\image005.jpg

 

Figure 6. Parts placement for translator board

 

*** NOTE: END OF DAUGHTER BOARD SECTION 

 

 

 

When you are ready to use the circuit, a onetime configuration of the microcontroller is necessary. This is because so many radios are supported that you need to tell the microcontroller which radio you are using. This configuration can be done through any of the interfaces, RS-232, USB, or C-IV. Any terminal program can be used, I will show how to use HyperTerminal. All communications are at 9600 Baud 8N1. The microcontroller is shipped with no particular radio selected. When you first power up the radio, send a character “S” (as in Setup) to the interface thru the terminal program. When prompted, enter the one number that corresponds to your radio. If the radio successfully received your radio type, the status LED on the PCB will illuminate right after you enter your radio type. Simply power cycle the radio, and it should come up to the default frequency shown in Table 4. Figure 7 reflects the process in HyperTerminal

 

 

Radio

Type

Level Translation required?

Default Freq (MHz)

Verified Operation

YouTube

Video

720A

1

No

14.275

YES

https://www.youtube.com/watch?v=pMKQQLi5oME

https://www.youtube.com/watch?v=v7thTKffiJo

551

2

Yes

52.525

 

 

560

2

Yes

52.525

 

 

251

3

Yes

146.520

YES

https://www.youtube.com/watch?v=R_2-jC5v1pg

255

3

Yes

146.520

 

 

260

3

Yes

146.520

 

 

451

4

Yes

446.000

 

 

701

5

No

14.275

YES

https://www.youtube.com/watch?v=vY-wNjTaUjQ

211

6

No

146.520

YES

https://www.youtube.com/watch?v=sza3H5QUYzA

245

6

No

146.520

 

     COMING SOON

 Table 4. Radio Types and default freqs.

 

 

Figure 7. Setup dialog in HyperTerminal.

 

 

If you successfully configured the chip and power cycled the radio and it came up on the proper default frequency, you are ready to use HRD. Everything should be sunshine and lollipops from this point on. Start HRD and open the “connect” dialog. Remember, we are emulating an Icom IC-7000 so we must tell HRD so. This is shown in Figure 8, but your COM port will probably be different. Make sure the speed and CI-V address match Figure 8 because HRD may try to change them.

 

 

Figure 8. HRD COM Port setup

 

 

Once connected, your display will look similar to the display shown in Figure 9. Since the Icom IC-7000 is crammed full of modern wiz bang features, there will be many more button that shown in my customized display. I suggest that you remove all the buttons except “PTT” and “MW”. If you are using an Icom IC-720A, also leave the mode button as shown. I threw in a wiz bang feature of my own. These radios did not come with memories, but I have given them one. Once you are on any given frequency, if you press the “MW” (Memory Write) button, that will become the default startup frequency when you first turn on the radio. It will be stored in non-volatile memory inside the microcontroller. On some radios, especially the 720A, the frequency controls on the radio should not be used if the remote control circuitry has been energized. If you do, the radio will lose sync and will need to be power cycled. It is advisable to use the “lock” button on the radio so that the VFO does not get accidentally bumped.

 

Go ahead and enjoy the fruits of your labor.

 

 

Figure 9. Ham Radio Deluxe display

 

 

Many thanks to Glen Williman, N2GW. I could not get information on interfacing to the 211,245, and 701 anywhere. Even Icom could not help me. I used Glens articles from QST and 73 and was able to figure these radios out. Incidentally, if you try to use the supplemental interface document from Icom for the other radios, be prepared for frustration. Not all the radios match the specification. One day I may make a website to post all of the interface information I have discovered.

 

 

73  Dave KA6BFB