Since electronic devices began to play a central role in various industries, connectors have become increasingly important as a key component in achieving reliable connections between devices. Among many connector types, D-shaped connectors (D-Sub connectors) stand out for their unique design and excellent performance, becoming the universal in connection solutions.

What is a D-sub connector

D-shaped connectors, also known as D-sub connectors, are a very common type of connector, named for their unique D-shaped metal housing. This design not only provides mechanical stability, but also provides shielding against electromagnetic interference (EMI) and radio frequency interference (RFI). The D-sub connector was initially used primarily in the military field, but due to its durability, ease of identification, and broad standard support, it soon expanded to commercial applications, including computers, telecommunications equipment, medical equipment, and industrial control systems.

D connector development history

The D-sub connector concept can be traced back to about 40 years ago, it originated in military connectors, and was originally designed to meet the needs of military applications. In 1952, Amphenol Corporation developed the earliest D-sub connectors, known for their unique D-shaped metal housing, a design that not only helped ensure the connectors were properly aligned and connected, but also provided good EMI/RFI shielding. Over time, the D-sub connector was standardized and became a common standard connector, widely adopted and available in many different types of specifications, such as DB-9, DB-15, DB-25, DB-37, and DB-50, where DB stands for "D-subminiature." In 1982, the industry introduced the first modular D-sub connector socket, which marked a significant advance in connector technology, and the modular design allowed D-sub connectors to be customized according to different application needs, increasing their flexibility and practicality.

D-sub connector function

The main function of the D-sub connector is to provide a reliable electrical connection for the transmission of power and signals. They can create stable interfaces between various electronic devices.

D-sub connectors can transmit many types of signals, including analog signals, digital signals, video signals, etc. For example, early computers used DB-9 or DB-15 connectors to connect serial ports. In addition to signal transmission, D-sub connectors can also be used for power supply, that is, to provide power to the device through a specific pin in the connector.

D-sub connectors are designed to operate in harsh environments, providing durability and reliability. They can withstand multiple insertion and removal operations without loss of performance.

The D-shaped housing of the D-sub connector helps ensure that the connector is properly aligned and connected, thus providing mechanical stability and preventing the connector from being inserted backwards.

The metal housing of the D-sub connector helps shield from electromagnetic interference (EMI) and radio frequency interference (RFI), which is especially important for sensitive electronic devices.

D-sub connectors have a standardized design, which means that products from different manufacturers are often used interchangeably, which increases compatibility and flexibility.

D-sub connectors have different specifications, including DB-9, DB-15, DB-25, DB-37 and DB-50, etc. These different specifications provide different numbers of contacts to suit different application requirements. Some modern D-sub connectors have a modular design that allows users to customize the configuration of the connector according to their needs, adding flexibility.

D-sub connector implements standards

D-sub connectors follow a range of standards to ensure their quality and interchangeability. These standards are usually developed by international organizations to guarantee compatibility and performance between connectors. Here are some of the execution standards related to D-sub connectors compiled by INFINITECH:

MIL-DTL-24308: This is a standard published by the United States Department of Defense that defines the technical specification for D-sub connectors. The standard covers the design, manufacturing and testing requirements of D-sub connectors to ensure they can meet the requirements of rigorous military applications.

IEC 60598-2-22: A standard published by the International Electrotechnical Commission (IEC) that covers the technical requirements for D-sub connectors, including dimensions, performance, and interchangeability. This standard is suitable for both civil and commercial applications.

EN 45545: This is a European standard relating to fire safety requirements in railway applications. While this is not a standard that directly addresses D-sub connectors, it could affect the design and material selection of D-sub connectors used in the rail industry.

UL/CSA: The Underwriters Laboratories (UL) and the Canadian Standards Association (CSA) are two North American certification bodies that have developed their own safety standards for connectors. D-sub connectors may follow these standards to gain acceptance in the North American market.

The Restriction of Hazardous Substances Directive (RoHS) is a European Union directive that requires electronic and electrical products not to contain certain hazardous substances. D-sub connectors must comply with the requirements of RoHS Directive.

REACH: The Registration, Evaluation, Authorisation and Restriction of Chemicals (Registration, Evaluation, Authorisation and Restriction of Chemicals) Directive is an EU regulation designed to protect human health and the environment from chemicals. D-sub connectors may also be required to comply with REACH regulations.

In addition, D-sub connector manufacturers may have their own corporate standards or specifications to ensure high quality and consistency of the product. These standards may include specific manufacturing processes, material selection, quality control procedures, etc.

D-sub (Type D) connector applications

Early computers used DB-9 or DB-25 connectors for serial communication, such as printers, modems, etc. DB-15 connectors have been used for video signal transmission, such as connecting monitors to PCS or other display devices. Some computer expansion cards and interface boards use D-sub connectors to connect external devices.

In telecommunications, D-sub connectors are used for data communication links and connections between network devices. In signal transmission and control applications, D-sub connectors are used to connect various types of telecommunications equipment.

In medical devices, D-sub connectors are used to connect monitoring instruments and sensors. In some cases, D-sub connectors are used to connect individual components of a life support system.

In industrial automation systems, D-sub connectors are used to connect control panels, PLCS (programmable logic controllers) and other control systems. In robotics, D-sub connectors are used to connect sensors, actuators, and other components.

In avionics, D-sub connectors are used to connect various parts of the flight control system. D-sub connectors are used in military communication systems and navigation equipment to connect various subsystems.

In the automotive industry, D-sub connectors are used to connect in-vehicle electronics such as engine management systems, sensors, and dashboards.

In scientific research, D-sub connectors are used to connect laboratory instruments and measuring equipment.

In video and audio systems, D-sub connectors are used to connect multimedia players, speakers, and other audio and video devices.

Installation method of D-type connector (D-sub connector

Prepare tools and materials

• D-sub connector

• lead

• Wire cutter

• Crimper or welding tool

• Electrical tape or heat shrink tube

• Screwdriver or wrench (if needed to secure connectors)

Installation procedure

1. Prepare cables

• Use wire cutters to strip the insulation at both ends of the wire, exposing a length of bare copper wire that should be long enough to solder or crimp the connector's pins.

2. Weld or crimp wires

• Welding:

  • Align the wire with the connector pin.

  • Solder the wire to the pin using solder.

  • Clean up excess solder and ensure that no short circuit occurs.

  • Wrap welding points with heat shrink tubing or insulation tape to provide insulation protection.

• Crimping:

  • If the connector supports crimping, use the appropriate crimping tool to crimp the wire to the crimp terminal of the connector.

  • Make sure the crimp is firm and not loose.

3. Secure the connector

• PCB installation:

  • If you are installing D-sub connectors on a printed circuit board (PCB), drill holes on the PCB according to the hole positions of the connectors.

  • Thread the pin of the connector through the hole in the PCB.

  • Solder the pins to the corresponding pads on the PCB using solder.

• Panel mounting:

  • For panel mounted D-sub connectors, you need to first cut holes on the panel, and the size and position of the holes should match that of the connectors.

  • Insert the connector into the opening from one side of the panel.

  • Attach the connector to the panel using screws or nuts.

4. Check the installation

• Verify that all wires are properly connected.

• Check that the connector is secure and not loose.

• Test the connector to make sure everything works.

Matters needing attention

• Before soldering or crimping, make sure all wires are properly peeled and of the same length.

• Make sure you do not damage the wires or connectors during welding or crimping.

• Care should be taken during installation to avoid unnecessary stress or distortion of the connector.

• If it is a panel installation, ensure that the seal between the connector and the panel is good to prevent dust and moisture from entering.

The above steps provide a basic guide, but the specific installation process may vary depending on the type of connector and application scenario.

D-type connector (D-sub connector) maintenance

clean

Use a clean, dry lint-free cloth to gently wipe the surface of the connector to remove dust and dirt. Avoid using acidic or alkaline cleaners to avoid corrosion of the connector surface.

For hard-to-remove stains, a light alcohol solution (such as isopropyl alcohol) can be used to clean, but be sure to dry completely before using the connector. Use a soft brush or cotton swab to clean the inner contact points of the connector.

moisture-proof

When storing and using D-sub connectors, try to avoid damp environment to prevent rust or corrosion. For connectors that are not used for a long time, you can consider using moisture-proof bags or sealed containers for storage.

anti-corrosion

For connectors exposed to corrosive environments, appropriate preservatives or lubricants can be applied to the contact surface to prevent oxidation or corrosion. Check connectors regularly for signs of corrosion and take steps to repair them.

Periodic inspection

Check the appearance of the connector regularly for damage, wear, or deformation. Check that the connector contact is intact and, if necessary, gently sand the contact using fine sandpaper to restore its electrical conductivity.

Functional testing

Use a multimeter or special test equipment to check the electrical performance of the connector and ensure that the connections between the contacts are good and there is no short circuit or open circuit.

Correct storage

Store D-sub connectors in a dry, well-ventilated place, away from direct sunlight. Use original boxes or specialized storage boxes to store connectors to reduce the risk of scratches and contamination.

Safe operation

When inserting or removing a connector, do so gently to avoid damage to the connector or cable.

Use the appropriate tool, such as a wrench or screwdriver, to ensure that the connector is securely secured in place.

If the connector is found to be seriously damaged or unable to work properly, replace the new connector in time. Select a replacement with the same specifications and type as the original connector to ensure compatibility.

The difference between Type D connectors and Type DB connectors

D-type connector (D-sub connector)

The D-sub connector (D-sub connector) is a widely used type of connector, named for its unique D-shaped housing. This housing design not only helps ensure that the connectors are properly aligned and connected, but also provides good EMI/RFI shielding.

Features:

Metal shell in the shape of D.

It can transmit power and signals.

Provides mechanical stability and electromagnetic shielding.

Various specifications, such as DB-9, DB-15, DB-25, etc.

DB connector

DB connector is a specific type of D-sub connector, and the "DB" in the name stands for "D-subminiature", which is a miniaturized D-sub connector.

Features:

Part of the D-sub connector series.

The number following DB indicates the number of contacts on the connector.

Common specifications include DB-9, DB-15, DB-25, etc.

It is widely used in computers and telecommunications equipment.

Differential summary

• "D-connector" refers to the general term for all D-sub connectors, and "DB connector" is a subcategory of D-sub connectors.

• When people refer to "DB-type connectors", they usually refer to D-sub connectors with a specific number of contacts, such as DB-9 (9 contacts), DB-15 (15 contacts), DB-25 (25 contacts), etc.

• DB connectors are particularly suitable for specific applications, such as serial communication and video signal transmission, due to their standardization and wide availability.

Give an example

• DB-9: Usually used for serial communication, such as connecting a mouse, keyboard, or old modem.

• DB-15: Previously used for video signal transmission, such as connecting monitors to computers.

• DB-25: Once used for printer ports and certain types of serial communication.