What is a Two Way Light Switch?

A two way light switch is a switch that can be used in conjunction with another two way light switch to control one light. Switching the light, or lighting circuit, with either switch will turn the light on and off, therefore they work independently of each other. 

A one way light switch is a switch that can control one light, or lighting circuit. It is also possible to use a two way light switch for one way lighting. In this case you just need to use the L1 (Live) connection, along with the COM (Common) connection. The L2 (Live) is left unconnected in this case. 

It is also necessary to use a two 2-way light switches in conjunction with an intermediate switch, or switches, if there are three or more switches controlling one light or lighting circuit.