D-series connectors have been in widespread use for many years, they were originally developed by Cannon in 1952 and are now part of CanT. The D-type connector has been used as a multi-way connector in many applications, but it is probably best known as the connector used for RS-232 serial links.

D-type connectors were originally called subminiature connectors, and connectors are now commonly referred to as D subminiature connectors. Although these connectors were small when they were first introduced, after so many years of development in the connector industry, many sophisticated connector products have been developed and designed in the world, so the D-type connector is no longer considered a true ultra-miniature. Connector.

D-type connectors usually consist of two, and sometimes more, connecting rows in parallel. The connector has a D-format metal shell, which not only provides mechanical strength to the connector, but also provides some limited screening, the metal shell of the plug and socket contacts to provide screening. Additionally, panel mount connectors are typically secured to the panel using nuts with additional threads that allow mating connectors to be secured to them to prevent loosening.

Additionally, the free connector can have a back shell that can provide shielding and can connect to a cable screen. Or if it's plastic, they can provide protection and also provide strain relief on the cable.