DB9 Male Welded Connector is the most common type of electrical connector. DB 9 connector is part of the D-sub miniature (D-sub) connector plug and socket family for computer and communication devices. DB-9 pins are arranged in rows of two, as one five-pin row above a four-pin row.
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. DB9connectors were commonly used for serial peripheral devices like keyboards, mice, joysticks, etc. Also, they are used in DB9 cable assemblies for data connectivity.