A 9-pin D-shell connector. This is a smaller version of the DB-25 connector and is also used for serial connections.

A communication interface that connects computers and UPS or other peripheral devices. The number '9' refers to the number of pins the connector has.

A standard 9-pin connector used for data transfer, as in RS-232 communications. Bittree's data patchbays feature standard DB-9 connectors on the backplane, and the sturdy, easily patchable Dual Bantam jacks on the front.

communications: Trapezoidal connector for printer and modem ports on ancient Macs pre-1986. Technically a DE-9.