DE-9
From Sega Retro
A D-shaped connector with two rows totaling 9 pins. The top row has 5 pins, and the bottom row has 4 pins.
Two types of DB-9 connectors exist. A male DB-9 connector has pins, while a female DB-9 connector has holes. You can only plug a male connector into a female plug or vice versa, unless you have a DB-9 gender changer.
ASCII diagram of a DB-9 connector:
\-------------/
\ o o o o o / \ o o o o / \-------/