Adaptor combines two 10/100mbit ethernet connections on to one 1000mbit Cat5/Cat6 cable. A splitter will be required at both ends of the cable.
Both connections will be limited to 10/100 speeds.
This cannot be used to plug two devices into one port on a switch, you must use a splitter on both ends of the cable and plug two lines into the switch.
This device is not a replacement for a switch or hub.