• USB RS-232 in NTVDM recommendations

    From Wall E. Weasel@21:2/121 to All on Thu Mar 11 21:06:00 2021
    Can anyone recommend a specific model or chipset for a USB RS-232 adapter that actually works *WELL* in a Windows XP NTVDM? I currently have one that uses the PL-2303 RA chip and the transmit is so very slow though the NTVDM. One with a driver that actually generates pseudo interrupts would be absolutely perfect.

    I'm aware that TX on most of these is going to be slower since it's not being interrupt driven. But on my current device that's actually not the bottleneck. Even using polling the FIFO TX buffer in the virtual UART is constantly filled, it's just not transferring the data to the device itself in a timely fashion. 3800 cps is the best I can manage on TX at a 115200 bps signal rate. I've borrowed and tried a few other devices and some are a little better, most are a lot worse.

    I'm asking here because it's probably one of the last places with people who would be doing something like this. It also is related to BBS development.

    Alternately, is there a more modern version of something like WinFOSSIL NT? The current version isn't able to be registered and the real mode portion of the driver sometimes clowns the NTVDM. It does function at full speed since the I/O is being done outside of the VM.


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    * Origin: The Basement Theory - Sciotoville, Ohio USA (21:2/121)