USB AExplanationA mouse is most commonly attached to a computer using a USB A connector. 6-pin mini-DIN connectors were used to attach a mouse in the past, however mini-DIN connectors are not used today. DB-15 connector with two rows is commonly used for joysticks. The DB-15 connector with three rows is used for connecting CRT monitors to the video card. The RJ-45 connector is used fro Ethernet network connections. USB B connectors are commonly used for connecting printers and scanners.