GE 45613 GE Z-Wave 3-Way Dimmer Kit with Terminals - Manual (Page 7)

Please Note: Z-Wave home control networks are designed to work
properly alongside 802.11 wireless computer networks, Bluetooth and
2.4GHz, 5.8GHz or DECT devices. Some baby cams, wireless video
devices and older cordless phones using the 900MHz frequency range
may cause interference and limit Z-Wave functionality. Many 900MHz
products have a switch to select channel “A” or “B”. You may find that
one of these channels will cause less interference than the other.
IMPORTANT NOTE ABOUT 3-WAY CIRCUITS
The term “3-way circuit” refers to a circuit with two switches
and one load (light) like you find at the top and bottom of a
stairway. There are many ways to physically wire a 3-way
circuit and it is important to understand how the circuit
you wish to upgrade to Z-Wave control is wired. Below is a
description of a typical 3-way circuit.
One of the ways to wire a two-switch/one-load circuit is to
route the incoming power through the first switch, then to the
second switch and then to the load. Although very common
and by no means a standard, it is the easiest to convert to
Z-Wave control. With this type of circuit, Switch 1 is replaced
by the Z-Wave auxiliary switch and Switch 2 is replaced with
the primary Z-Wave switch. The auxiliary switch does not
actually control the power; instead, it sends a momentary
voltage signal through the traveler wire to the primary switch
which in turn, controls the power to the load.