Re: 486 PC. Keyboard problem.
Assuming the serial printer works (tested on another pc?) then you could send text strings to it from MSDOS then plug it into the other ports to check them.
Without loading a terminal program, the MSDOS "mode" command will show which ports are present e.g.
mode
Status for device COM1:
-----------------------
Baud: 1200
Parity: None
Data Bits: 7
Stop Bits: 1
Timeout: OFF
XON/XOFF: OFF
CTS handshaking: OFF
DSR handshaking: OFF
DSR sensitivity: OFF
DTR circuit: ON
RTS circuit: ON
then to send a string to that port:-
echo 1234567890 > com1:
__________________
George
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