Fortunately, my father had the USB version of the cable (OPC-478U) in his collection, and loaned it to me. The CS-T8 software was (thoughtfully) included on a USB flash drive I got with the radio (along with the manual in .pdf format, and several other bits of documentation.)
So I plugged the USB cable into my PC, and Windows 7 installed drivers without prompting me. Then I connected the other end of the cable into the radio, set the radio to CLONE mode, and double-clicked on CST8SU.BAT to start the software.
DOSBox. DOSBox is a DOS-emulator that runs fine on most any modern version of Windows. So I downloaded and installed the latest version from the web (I was a couple minor revisions out of date), now I needed to know what serial port was being emulated by the USB cable.
To do this, I clicked the downward triangle that's the new Win7 system Tray, then right-clicked on the USB icon and chose "Open Devices and Printers". Double-clicked the "USB <-> Serial" Icon, then selected the "Hardware" tab. Here is where the COM port being emulated is listed (in my case, it's COM3):
Armed with this info, I needed to update the dosbox.conf to use this virtual serial port. I added the following line to my config:This line basically says that the DOSBox serial port 1 (COM1) should be mapped to the Windows 7 COM3. Then I copied the TC8A software into the DOSBox directory (I put it in a ./TC8A folder), and started DOSBox. I then connected the cable to the radio, and started the radio in CLONE mode.
At the "C:" prompt, I typed 'TC8ASU' to start the software:
This method should work for most any older DOS-based software. Check out the DOSBox website for more info, but it's my preferred tool for situations like this, particularly since i can map directly to existing hardware for serial connections.