Power from the light to the switches. Each set of terminals is one of the toggle positions.

How To Wire 4 Way Switch Devices Amp Integrations
4 way switch power at 4 way. 4 way switch wiring 4 way switches provide switching from three or more locations. If more than three switches are needed simply place more 4 way switches between the three way switches. Another 143 wire is used to connect another three way switch where the circuit will end. A 143 wire is then used to go to a four way switch. In this scenario you will have a 142 wire coming from the light fixture into a three way switch. A 4 way switch could be used as a 2 way or onoff switch.
But if by common you mean the white wire or neutral do not connect it to the switch or you will get a direct short between the hot and the neutral. As you will see most 4 way switch wiring is placed between the wiring of two 3 way switches therefore a 4way switch is installed with two 3way switches. The hot source is connected to the common terminal on the first switch sw1 and the hot terminal on the light fixture is spliced through all the light fixture to the common terminal of the last switch. Starting with safety and understanding 1. 4 way light switch with power feed via the light. Four way switches are used in combination with three way switches.
A four switch configuration will have two 3 way switches one on each end and two 4 way switches in the middle. If the device is still. Turn off electric power. A two wire cable c2 is run from the light to the first switch sw1 and a 3 wire cable runs between all the switches. Four way switches are used to control lighting from three or more locations. Turn on the light or device being controlled by the 3 way switches if you already have them.
This circuit diagram shows wiring for a 4 way circuit with the power source at the light fixture and the switches following. 4 way switches have four terminals each with two pairs of travelers one set usually black and one set usually brass color. Return to location you plan to wire to verify that there is no electric flow to that device. Conventional 4 way switch wiring. 4 way switch diagram options. There are four terminals that provide two sets of toggle positions on a four way switch.