A notebook expansion port can be one of any number of slots in a notebook computer that allows users to plug in devices or connectors. Examples include a card reader, a USB port or an RJ-45 port.
Card readers access the data on memory cards in a number of different formats, though the most common formats are compact flash and SD. USB ports are used for a wide range of devices and accessories, such as external hard drives. Powered USB ports can also charge phones and other small devices. RJ-45 ports are for Ethernet cables. Some other expansion ports that may be found on a notebook include Thunderbolt, Firewire and ports to attach docking stations.