Solve the router port number is not enough:This adapter Advantage Design: A notebook in three different fixed position often back and forth use, this is a very trouble, the network cable to lead to broken, this rj45 1 to 3 ways RJ45 ethernet splitter help you do not have to pull back and forth cable. Solve the problem of insufficient number of rooms installed network cable: If you have one network cable installed in your room, you havethree computers (or other devices: Such as a TV) you use this rj45 1 to 3 ways RJ45 ethernet splitter help you do not have to pull back and forth cable. NOTE: This Ethernet splitter allows all(three) computers to share one Ethernet line ONE AT A TIME, but it doesn't support both computer to connect onto the internet simultaneously.