Hi,
I have a plotter HP9862A and a calculator HP9815. Unfortunately I don't have any cables to connect them, only the BCD I/O module for the calculator.
The manual for the plotter is on the museums CD, but does not give any hints, maybe because it was written in the time of the HP9810, the precursor of the 9815.
Who knows what kind of interface the plotter does have?
Thanks,
Thomas