RJ45 connectors are the kind that are used for Ethernet jacks, but they make great general purpose connectors when you need a lot of conductors. This is a small PCB that brings out the pins of the RJ45 connector to an in-line 0.1″ footprint. Use with break-away headers for breadboarding or create your own RJ45 cable. Check the related items for Ethernet cable and connectors to go with it!