2 Switch Wiring Diagram. Take the white wire leading to the second box and mark its end black too. 3-Way Intermediate Switch to Touch Dimmer Conversion Wiring.
Take the white wire leading to the second box and mark its end black too. A commonC L1 and L2. Wiring a two way switch.
The COM L 1 and L 2 are the three terminals of the two-way switch.
If you need to know how to wire a ceiling rose with two way switching check out the links below. Each of the gangs or switches above in Fig 2 of which there are two work like this Fig 3. 2 Humbuckers3-Way Toggle Switch1 Volume1 Tone1 Push-Pull for Dual Coil Tap of Both Humbuckers. Essentially 2 black wires are attached to the bottom dark screw of one switch.