HDTV Supply Sewell Spider MX0402-321 Operating Instructions Manual page 12

The IR emitter use low power infrared diode as emitter so that it will not
interface other infrared signal. Please stick the IR emitter near to the IR window
of the STB or DVD.
5. IR receiver cable extender jacks.
When the display device is not near to the matrix, the IR_RX cable will be
to short. There are a pair of jacks to extend the IR_RX cable. Customer or
installer can use the headphone cable or 4-line telephone cable to make the
IR cable extender.
Use the male jack and female jack to extend the IR_RX cable like the picture
below.
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