Sennheiser Set 810 Notice D'emploi page 24

Where to place the transmitter
Place the transmitter so that the
infrared light beam is pointed
directly at the receiver, i.e. there
should be no obstacles in the light
path between transmitter and
receiver. Guide the cables
backwards.
Avoid exposure to direct sunlight.
Direct sunlight may interfere with
the reception and may damage the
transmitter.
Pull the power supply unit out of the electrical outlet when the unit will not
be used for extended periods of time.
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