All switches are toggled down to create an open path, light is off.
Switch 1 is toggled up to create a continuous path, light is on.
Switch 2 is toggled up to open the path, light is off.
4-Way Switch Wiring Using 4 or More Switches
4-way switches have four terminals each with two pairs of travelers (one pair usually black and and the other pair brass color). A three switch configuration will have two 3-way switches, one on each end and one 4-way switch in the middle.
In the diagrams below, switch 1 common terminal connects to line voltage.
Switch 1 pair of traveler terminals connects to the top or bottom pair of traveler terminals on switch 2.
The other pair of switch 2 travelers connect the to a pair of traveler terminals on switch 3.
The other pair of switch 3 travelers connect the traveler terminals on switch 4.
The switch 4 common terminal connects to the load (lights).
Ground connection is not shown in these diagrams.
4-Way Switches Page 2
4-Way Switch Wiring Diagrams