EDIT:
I should have visited my son earlier. I saw him yesterday. He figured it out in about two minutes. That's a long time for him -- he's in charge of enterprise software at a LA area college.

...and... it turned out... that I was using the wrong cable type. As soon as my son said "that should work" and it didn't, I inserted the null modem and voila: it worked!

ORIGINAL POST:
I swear I remember there was some way to change the COM port from 1 to something else. Can it be done?

Still trying to make a modern Windows 10 or 7 computer (or even an XP!) able to edit the programming in a Marantz RC5200.

Hoping Daniel can weigh in here as well.

I don't think there ever was a registry entry to change the stating Port number that TSS or ProntoEdit used.

The change to the COM port must be done via the Windows Device Manager and the device driver you are using must support it.

Start->Run->Devmgmt.msc

Generally speaking, the Pronto needs to be connected to the first available COM port. I can’t recall whether a COM port not existing is good enough for it to try the next, but if there’s a COM1 and the remote’s connected to COM2, then COM1 has to be busy or the connection will fail. There is no configuration possible, it’s automatic.

It will also have to be in the standard COM1 through 4 range, not COM12 or something.

[Link: remotecentral.com]

Also, make sure you’re using a proper Pronto cable and not one with reverse wiring. To verify that everything’s good between the remote and your PC, you can use a terminal program to connect to the remote and see if you get the boot up text. Instructions here:

[Link: remotecentral.com]

If you can still find Stuart's Tonto program, I think it might not have had the same limitation.

FWIW, Tonto is hosted here [Link: github.com] . (It is internally used by IrScutinizer to read/generate CCF files.)

Ernie,

The title was updated to say S O L V E D.

So, what was the solution?