Next to the mirror base: communication window
(illustration).
Heat-insulating glass windscreens may have an infrared-reflecting coating and can be heated wirelessly with some equipment levels.
To ensure that any radio equipment purchased as an accessory, e.g. a toll system, functions properly, there are uncoated areas
(communication windows) on either side of the interior mirror → Fig. 1.
The uncoated areas should not be covered either from the outside or the inside, nor should any stickers be applied to this area as this
could cause a fault.