When set to "uplink" (as opposed to "normal"), the Uplink switch on the PN400TP swaps the send/receive pair on Port 1 so Port 1 can then be connected with a normal RJ45 patch cord (as opposed to a cross-over patch cord) to a spare port on, for example, a Netgear RP614 router, and then ports 2,3,4 on the PN400TP can share the bandwidth of the port on the router to which the PN400TP has been "uplinked".