Dipsvitch standards

Hi

In old plotters and Com port printers there use to be one or two rows
of dipsvitches .
I recall that there are sort of a standard about what the individual
svitch cover --- set on or off depending what protocol , how many
stopbits , flow control aso.

My problem are my old Calcomb pen plotter ; it will work for some 3kb.
of code send, but after that it Error --- it say that there are a
parity foult , with different setup ,that's when I by software tell it
I want to use Xon/Xoff it say there are a buffer overflow.

Now if I just knew the standard rules for the svitches I could make
sure that the hardware are ready to respond and cut the data flow when
the buffer are filled, ------- any help here, please.

P.C.