D-sub connectors contain two or more rows of parallel contacts, with a characteristic D-shaped metal shell around the contacts. The housing not only provides mechanical support and ensures correct orientation, but also shields electromagnetic interference (EMI). There are several methods for connecting the system circuit to the contacts in the D-sub connector, including crimping, solder cups, PCB soldering, PCB crimping, and wire-wound connections. In many cases, a locking system is used to ensure that the connector remains in a matched state under shock and vibration conditions.
D-sub connectors are sometimes confused with the Micro-D family and the SCSI attachment family (featuring connectors like the HD-50 and HD-68). These products are separate and distinct from D-sub connectors. D-subs are sometimes referred to as “rectangular rack and panel” connectors and often carry vernacular references such as DB9, DB15, DB25, DB37 and DB50 where the numbers refer to the connector's pin count.
