An RJ45 coupler is the perfect inexpensive solution for extending your network cable's reach. The coupler allows you to connect two RJ45 connections to extend your UTP. The coupler is passive, which means it requires no additional power source. Simply plug in the two Male RJ45 jacks that you need to connect and voila! You've extended your network.
The RJ45 coupler is also compatible with RJ11, RJ14 and other smaller form factor registered jacks. The only difference between a RJ11 coupler(telephone coupler) and a RJ45 coupler is the number of wires used. Using an RJ45 coupler with RJ-11 cables works flawlessly.