Hotline to L1 on both switch Common (or) traveler connecting the COM on both switches Load goes from L2 on both switches (To light)
My house is wired this way. Is there a US electrical reference that I could give a switch supplier? (Zooz)
EDIT: Adding the colors of wires in my boxes, I have neutral in the box but they are just a pass through.
Stock US 3 Way - change your wiring connections.
Line Power into first switch on the black terminal.
Both Travelers between switches on brass terminals.
Load power out to the load on second switch's black terminal.
No connection directly from first switch to Load.
No connection directly from Line power to second switch.
Drawn with white neutral, not pink. You end up with an extra wire between boxes. It doesn't matter if you use the "orange" or the "black" for the second traveler.
In the U.S. it is called a "California 3-way" or a "coast 3-way".
It was commonly used in the knob-and-tube days, when current-balancing was not yet a requirement. It is no longer installed by U.S. electricians.
It is quite safe if all the conductors are bundled into a single cable or conduit. Sometimes this requires a 12/4 or 14/4 NMS cable, which can be hard to find.
The circuit in your drawing can easily be converted to a modern traveler-pair 3-way. If you do this you will no longer be in conflict with the assumptions of the Zooz people. Ecnerwal describes how to do this in his answer, and FreeMan has modified your drawing to show the changes.
Smart switches don't depend on the usual "common + 2 travelers" arrangement. You are going to be re-wiring both boxes to match the requirements of the smart switch.
The only thing you need to identify is the cable between switches (a cable is several wires bundled together in a sheath). Then, assign the colors in that cable according to the instructions. Which will require that you re-define every wire, since these smart switches use the wires completely differently. As such, the prior configuration does not matter.
A common mistake here is to "not read the instructions" and expect it to wire like a common 3-way switch.
Their instructions show the wiring "before", but you only need to concern yourself with cable identification. You'll be re-defining what all the wires do.
Weirdly, their "before" drawings show only 1 traveler. I guess they never got the bulletin on how "conventional" 3-ways work, as they have 2 travelers. Well, it doesn't matter.
The actual name of this circuit is California, West Coast three way circuit. By strict definition, this type of circuit didn't have any neutrals in the switch boxes so it's a "modified" California three way. Follow @Ecnerwal's instructions if you are going to change to normal conventional wiring.
