On 4/13/2020 6:46 PM, Billy wrote:
The other issue is, lot of the newer COM port computers have a 16550 UART, or 16550a UART. This is also what USB to Serial adapters will emulate. But, some of the older computers had a
16540 UART and that is what some of the radios and software expect to find. Some radios and/or their software simply need an old computer, slower clock cycles, pure MS-DOS and a 16540 UART. Other radios are more forgiving.
There are differences in the uarts over the decades. But I'm not sure it's near as much of an issue as the typical USB to Serial device issues.
Remember, 16550's became a thing in 286 days, and by 386 timeframe was increasingly the norm. Many of the "you have to use an old laptop" computers used successfully for DOS based RSS/CPS have 16550's.
But if it is an issue with dosbox and windows, I found one writeup from a british ham that had the magic answer.
The trick is to go into Windows Device manager, open the serial device advanced properties for the device in question, and set the buffer to 0. That's usually all it takes.
I had several work before I learned this trick, but now I do this if I see any serial issues with older SW.
But the biggest single issue I've seen is non-FTDI USB to Serial adapters. The Prolific brand usually will not work with DOS based programs.