A few months ago, I bought this Kouwell KW-524E(S) IO card on eBay. I have a PC AT machine with one internal DB25 serial port that shows up as COM1 in MS-DOS. The Kouwell card, which has a DB9 serial port that I want to use, shows up as COM2. While serial communication works on the internal DB25 serial port (e.g. Kermit file transfers), I cannot get it to work on the Kouwell card's DB9 serial port.

I found the following documentation for a Kouwell KW-524E:

https://www.minuszerodegrees.net/manuals/Kouw … nfiguration.pdf

https://stason.org/TULARC/pc/io-cards/I-L/KOU … -card-KW-5.html

...but neither mentions anything about the DIP switch that is sitting next to the DB9 serial port (as pointed to by the red arrow in the attached image). I am guessing that the (S) in the name on the card refers to this being some variant of the KW-524E card that comes with a (S)witch.

Unfortunately, I cannot find any documentation specifically for a KW-524E(S) IO card that describes what the DIP switch does. I am sure that it is configured incorrectly and causing serial communication not to work properly. I have already made sure to open and close the appropriate jumpers for making the DB9 port (1) COM2, (2) use IRQ 3, and (3) the only port enabled for serial communication on this card.

Do any of you know anything about this card and what this DIP switch controls? Thank you.