Just to update this thread for future reference purposes:
I did finally track down the
software (both EX1726 and EX2144). EX2144 is for the ICOM-710RT. The necessary cable you can find on eBay or other
electronics sources.
Now for the potentially more difficult part. These are both MS-DOS applications which require direct access to COM port registers. This means they will NOT
work under Windows (including Windows emulated MS-DOS). They will run under Windows emulated DOS, but their COM interface won't
work properly. You must run them under native MS DOS on a machine with a physical
serial (COM) port. Most newer machines don't have
serial ports anymore. Just happened that in my case I had access to an old machine which had one.
To deal with the MS-DOS issue, what I did was create a bootable MS-DOS CD which also contained a copy of EX2114. There are several pieces of
software readily available that will do this for you. I used
Create Ms-Dos BootCD - Hiren's Bootable CD - www.hiren.info. Then it was just a matter of hooking it all up and booting the old machine using the MS DOS boot image.
The boot image I created was MS-DOS 5.0.
The change itself was quick and easy and I prefer it to making uncertain
hardware modifications.
Re cutting diodes on the 710RT. I have not tried this solution and I have read conflicting reports about whether it works on the RT specifically.
Note I did not use this software to enable operation on any frequencies for which the
radio is not authorized. I only used it to enable storing the TX frequency with user memory channels (a feature which I can't fathom why
ICOM turned off in the first place).