2 is send wire and goes to rcv on the other end
3 rcv (uhm you guess this one)
5 ground - if memory serves. its midnight no the memory is a little shaky.
the drain wire is often not used. that'd be chassis ground.

you may need to reverse 2 and 3 - not having access to your devices pinouts at hand. sometimes they are backwards. this goes back to modems and dumb terminals - of course then the pins were 2,3 and 7 on the db25 connector.

if you can't tell what wire goes to what pin break out your ohm meter.

hope this helps.