Yamaha YAS-209 Owner's Manual page 14

Part names and functions of the subwoofer
The part names and functions of the subwoofer are as follows.
a
Bass reflex port
b
PAIRING button
Use to pair the center unit with the subwoofer
manually (p.42).
c
STANDBY indicator
Shows subwoofer's status (p.15).
Front panel
a
d * indicator
Glows when the center unit and subwoofer are
connected wirelessly.
e
Power connector
Connect the power cord (p.20).
Rear panel
14
En
b c d
e