On-Board Diagnostics [OBD] is a vehicle bus used to monitor engine functions. OBD II is the second generation of that interface. The graphic below details a male OBDII connector to female OBDII connector Cable assembly.
OBDII to OBDII Assembly
OBDII Gender Changer
This is one of a number of pages showing OBDII cable assemblies
Most of the other pages show a cable with one end having something other than an OBD connector.
OBDII to DB15 pin Cable
Female OBDII to 2x2 pin Cable
Right Angle Male OBDII to DB-9pin Cable
Male OBDII to DB9-pin Cable right angle
Male OBDII to Male DB9-pin Cable
Male OBDII to Male DB15-pin Cable
BMW to Female OBDII Cable [vehicle specific connector]
Back to the main OBDII description page, or OBDII pinout, Signal Assignments
Primarily the links to OBD cables only show a picture of each type. But is page link does show a different connector style, or two different connector styles.