After many years of asking questions here and getting help, I finally have something to contribute! The software had some bugs and didn't work out, but I was able to "hack it out" with a free software solution. I threw out my ancient MacBook Pro, so these instructions are for PCs only:
Tools needed for the job:
1 - A USB to Serial Port Adaptor. I bought this -
https://www.amazon.com/gp/product/B000067RWK/
2 - A pair of Needle Nose Pliers
3 - Free Putty Software -
Download PuTTY: latest release (0.74)
The physical adaptor is very badly deigned because the metal end pieces don't screw off, and as is, the pins will not fit into the holes of the interface on the back of the AOR 3000 because the AOR's 25 pin interface has the same end pieces and they hit each other which physically blocks the pins from fitting into the holes. I tried unscrewing the the end pieces from the AOR, but they hold it in place, so I had to reattach them.
Step 1 - Use the pliers to detach the metal end pieces. Whoever's reading this probably has better technique than I, but If I was able to pull them off without ripping the entire metal plate off, then you should be able to do it as well.
Step 2 - Install the drivers for the adaptor. The adaptor came with a CD. If anybody doesn't have a player and can't find the drivers online, let me know and I'll upload them somewhere. Reboot, even if not prompted to.
Step 3 - Configure the port settings and make note of the virtual COM port number that was assigned. Launch the device manager. You will need administrative credentials if you aren't logged in as a local administrator. Expand Ports (COM & LPT) - Double-Click on Prolific
USB-to Serial Comm Port. If you aren't an admin, click on "change settings" and enter the admin credentials. If you are an admin, just
double-click on port settings. Set Data bits to 8, parity to none, and stop bits to 2. Flow control appears to be irrelevant, as I can get
Putty to control the radio with all of the different options. You will have to figure out the Bits per second by trial and error. The AOR
3000 manual specifies 4800, but my unit needed to be set at 9600. The AOR 3000 can be opened and tweaked and it appears that the
previous owner set the baud rate to 9600. Once you are able to get Putty to open the COM port with the same settings as the virtual
port, you will know the settings are correct.
Step 4 - Connect the adaptor to the AOR 25 pin interface and the USB end to to an available USB port and power on the radio. If you are out
of USB ports, buy a powered hub. I love these -
https://www.amazon.com/gp/product/B07G8CMR18/ I have no brand affiliation, but
whatever you do, buy a powered hub.
Step 5 - Launch and configure Putty. The default install location will be "C:\Program Files\PuTTY\putty.exe. Select a Serial session and change
the defaults to match your port defaults. Select session, Serial. Give it a name. Save. Load - Open. For future Putty Sessions -
Load - Open. If you want to see the welcome screen, power up the radio after Putty opens the port.
How to control the radio from within Putty:
Directly input the frequency followed by the 'Enter" Key, such as 105.9, or .610. To change the modes:
WFM : the "w" key followed by 'Enter."
NFM : the "n" key, followed by "Enter."
AM : the "a" key, followed by "Enter."
USB: the "u" key, followed by "Enter."
CW : the "c" key, followed by 'Enter."
In spite of my term paper on the subject, there is one thing that puzzles me. With some Putty sessions, but not all, as soon as I change modes, the volume gets very low and without the terminal command to fix it, will only be returned to normal if I power off the radio and turn it back on. To restore normalized volume, simply hit the "g" key, followed by "Enter." I'm neither a good programmer nor an AOR expert. I figured this out by trying every key and praying one of them would work to fix the volume. The volume problem is either a weird intermittent anomaly, or is attributed to me not doing the same things for different terminal sessions. If anybody figures this out, please let me know. Also, I have no idea whether the "g" command is a native RS232 command or AOR specific. If anybody know this, please let me know as well.
I had a ton of fun figuring this out and sharing, and hope I'm helping out some people. SDR's are so cheap and so good these days, that I don't think a lot of people would have bothered to do this. The AOR AR-3000 is such a beautiful radio, that the paperweight status was bothering me, and it would have killed me to have had to throw it out. Without the PC interface, my AOR is useless, as now, neither the dial pad. nor the buttons work! At least the necessary volume control and squelch knobs, as well as the power button are working.
I enjoyed "hacking this out." Hope it helps some folks.