An Overview of D-sub Connectors

D-subminiature connectors, sometimes called DB connectors or D-subs, are a versatile type of electrical connector. They derive their name from the unique D-shaped shield which protects all sides of the connector from both mechanical and electromagnetic interference. Additionally, the shields’ asymmetric shape ensures that it only attaches to its corresponding connector in the correct orientation. Within the D-sub, there are two or more parallel rows of pins (in the plug) or jacks (in the socket) aligned to match the equivalent contacts in the other half of the connector. The pins or jacks usually feature a gold tip surrounded by a layer of insulation made from a variety of materials such as glass or PBT, a plastic used for insulation.

There are many ways to differentiate D-sub connectors, but the most common ways are by their number of pins or jacks, the connection method, or the connection duration. Letters A through E and their corresponding numbers are used to indicate the number of contacts in the shell of each connector’s plug or socket. For instance, the smallest type of D-sub is the DE-9 or DB-9, consisting of a plug with nine pins connected to a socket with nine jacks. Certain D-subs have HD attached to their name, indicating that they are high density connectors. HD D-subs feature a closer arrangement of pins and jacks within the shell, hence their name.

Many D-subs vary in how they connect their contacts with the system circuitry. A main advantage of D-subs is that they are well-suited for locking technology. Locking technology refers to hardware that keeps the plug and socket component in the mated position - typically by way of screws inserted into threaded holes attached to the metal shell of each part. Locked D-sub ports are more resistant to tampering and jostling than other ports such as USB, HDMI, or Thunderbolts. The third way to identify D-sub connectors is by the duration of their connection. D-sub ports offer a broad range of connecting styles for other uses such as crimping and soldering. Crimping is ideal for temporary and at-home connections, while soldering is used for more permanent connections.

When they were first invented in the 1950s, D-subs were the most compact and effective connectors on the market. Years later, personal computers featured D-sub ports for a wide range of external connections such as printers and ethernet components. Despite their popularity and versatility, D-sub connectors, like any electrical component, have disadvantages. Their large size and unpredictable data transfer speeds have made them susceptible to replacement by newer technologies such as USB ports, particularly in applications including connecting personal computers with external devices. Another disadvantage is that implementation of D-subs requires an additional power support, as D-subs contain lines for data and communication but not power.

Regardless of their disadvantages, D-sub connectors are still the best option for many applications. For DIY projects and custom-tailored electronics applications, where the range of connection options make frequent re-wiring and fine tuning simpler, D-sub connectors flexible wiring and secure connection make them a great choice. Additionally, D-sub’s low cost and high reliability make them useful for a range of media applications such as video graphics array connectors in television, gaming, and recording devices. Finally, D-sub connectors are more rugged than faster, more compact alternatives, making them an appealing option for portable uses where they could be subjected to jostling and movement. Whatever D-sub connector needs you have, ASAP Fasteners can help fulfill them.


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