I don't have a cable, but consulting my 1988 copy of the Apple Peripheral Interface Guide, the only DE-9 Male to DE-9 Male cable is the 590-0197.

"Used to connect the following devices: Macintosh to a Modem 300 or Modem 1200"

Cable is wired as follows:

DE-9 Male---DE-9 Male

3 & 8---3 & 8

5---9

6---6

7---7

9---5

(Hope the diagram makes sense - the forum collapses multiple spaces down to a single space, so I couldn't line things up in columns).