This is a common connector used in many computer, audio/video, and data applications. The official name is D-subminiature, but many people call it “D-sub” or just “DB”. The connector gets its name from its trapezoidal shape that resembles the letter “D”. Most DB connectors have two rows of pins. Common types of D-sub connectors are DB9 and DB25, used on PCs for serial and parallel ports.

One special type of D-sub connectors is the High-Density DB style, which looks just like a regular DB connector, only with pins that are slightly smaller and placed closer together. This is typically referred to as an “HD” connector. HD connectors often have three rows of pins instead of two. The most common HD connector is the HD15, which is found on PC video cards and monitors. DB- and HD-connectors use thumbscrews to secure the connector in place.

Another type of D-sub is the MD, or Micro DB connector. This connector is slimmer than a standard D-sub, with pins even smaller than the ones used on HD connectors. The MD is also commonly called a “half-pitch” DB connector. These are often used in SCSI applications, and the most popular types are the MD50 and MD68 connections. MD-connectors can use latchclips or thumbscrews as anchoring mechanisms.

D-sub connectors are usually described by the total number of pins that they can hold. In some cases, a DB25 connector may only have 4 or 5 pins loaded into it; however, it is still called a “DB25” connector and not a “DB4” or “DB5”. Another example is the HD15 connector used by monitors—most monitor cables only are loaded with 14 pins, but it is still called an HD15 connector.

Where are DB9 Connectors used?
DB9 connectors were once very common on PCs and servers.  DB9 connectors are designed to work with the EIA/TIA 232 serial interface standard, which determined the function of all nine pins as a standard, so that multiple companies could design them into their products.  DB9 connectors were commonly used for serial peripheral devices like keyboards, mice, joysticks, etc.

Today, the DB9 has mostly been replaced by more modern interfaces such as USB, PS/2, Firewire, and others.  However, there are still many legacy devices that use the DB9 interface for serial communication.

What does L-com carry for DB9 Connectors?
L-com has a huge variety of DB9 products, including connectors, adapters, and cables.  See links below for types of products using DB9.