D-type connectors most commonly consist or two and sometimes more
parallel rows of connections. The connectors have a D-format metal
shell. This not only provides mechanical strength to the connector,
but it also provides some limited screening as well - the metal
shells of the plug and socket make contact to provide screening.
Also the panel mounting connectors are typically secured to the
panel using nuts that have an additional thread that allows the
mating connector to be secured to it to prevent it working loose.
Additionally the free connectors can have backshells that can
provide screening and can be connected to the cable screen, or if
plastic, they can provide protection. Strain relief on the cable is
also provided.The pins in the more common connector types with two rows of pins
(e.g. 9, 15, 25 and 37 way) are spaced approximately 0.108 inch
(2.74 mm) apart with the rows spaced 0.112 inch (2.84 mm) apart.
High pin counts and higher pin densities can be achieved using more
rows of pins.
