La Crosse Technology WS-2306 Operation Manual page 11

Using the AC adaptor to operate the base station will also supply
power to the sensor if the cable is connected to it. Batteries used for
433MHz transmission may be left in the sensor when using cable
connection for power back up in case of AC power failure. A loss of
power would desynchronize the base station and the sensor and no
weather data will be received. To synchronize the units so that the
weather data can be received, press and hold the PLUS (+) key for 2
seconds. However in general, batteries that will not be used for long
periods should be removed to avoid leakage.
Wireless 433MHz transmission:
Using 433MHz wireless transmission of weather data from the sensor
to the base station will provide users greater freedom as to where
units can be positioned without the need to be restricted by cable.
Note:
If no outdoor weather data is displayed or the signal to the sensors is
lost during setting up, mounting, changing of batteries to the sensor or
plugging or unplugging cables, simply press and hold the PLUS (+)
key for 2 seconds and a short beep will sound to synchronize the
base station to the sensors. Without synchronization, weather data
will not be received.
10