Sony UTX-B03HR Operating Instructions Manual page 15

Symptom Cause
The transmitter The infrared receptor on the transmitter is too far
channel cannot be set from the infrared transmission port on the receiver.
with infrared
transmission.
Interference from infrared communications
between other devices or from direct sunlight is
present.
Solution
Reduce the distance between the infrared receptor
on the transmitter and the infrared transmission
port on the receiver to within about 20 cm (8 in.).
The transmitting distance is reduced when
interference from strong sunlight, for example, is
present. Place the transmitter and receiver as
close to each other as possible.
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