Sennheiser HDI 302 Instructions For Use Manual page 47

CHANNEL SELECTOR SWITCH ON THE HDI 302
The HDI 302 stethoset receiver features a channel selector switch which lets
you choose between the following options:
With the switch set to position " ", a stereo signal is received
(channel 1 right, channel 2 left).
With the switch set to position "I", only the signal from channel 1 is received
(carrier frequency 2.3 MHz). This mono signal is supplied to both headphone
systems.
With the switch set to position "II", only the signal from channel 2 is
received (carrier frequency 2.8 MHz). This mono signal is supplied to both
headphone systems.
Please adjust the volume as usual.
20