A D connector contains two or more parallel rows of pins or sockets surrounded by a D-shaped metal shield that provides mechanical support and some screening against electromagnetic interference.

The D shape guarantees correct orientation. The part containing pin contacts is called the male connector or plug, while that part containing  contacts is called the female connector or socket. 

Some common pin orientations are shown below.



Examples of Warner products that use a D connector interface include the Intralux DC 1100 light source, Oxystreamer O₂ and CO₂ Gas Controller, VC-6 and VC-8 valve controller systems, and the inNO-T Nitric Oxide Measuring System. 

A typical cable with D connectors is shown below.