Click on pictures for larger versions.

I've made a few of these interfaces and they have all worked fine. Though if you make one, you do it at your own risk. Don't come crying to me if you blow up your PC or radio.

My interfaces have worked OK powered from the RS232 port, though you may have to use an external power supply if your computer has a low power serial port (some laptops are like this) or if your software does not drive the hardware handshaking lines high.

I found this diagram on the internet.

And made this PCB using "Easytrax". This file is a PDF, so you will need to have Acrobat installed on your PC.

You can make PCBs with photo inkjet paper a laser printer and your XYLs iron.

I used some "press n peel" which was left over from another job.

You may need to flip the PCB layout, if you are using some other method to get the layout onto the bare board.