Phonic Ear HC-421R Stereo Auditory Training FM System
The Phonic Ear HC-421R Stereo FM Training System
was designed for use in classroom settings. This 1965 model was one of the forerunners of our modern FM classroom systems.
It consisted of the wireless microphone which the teacher wore and
the pager-like FM receiver the student wore around their waist. The
receivers had four snap on clips on the back which connected the unit to
a special belt worn by the student. |
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The students wore receivers (earphones with custom ear molds attached)
in each ear. It was called a stereo system, but it was really a
dual-mono system as there was only one sound channel. There were
separate volume controls for each ear.
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The back of the HC-421 FM receiver showing the labels for the
controls that are located on the sides. |
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A plug-in crystal module (red part) was
used in each receiver to coordinate the frequency of the transmitter
with the receivers. The crystal modules were color coded with different
colors to designate the frequency. There are no markings on the modules
to indicate which frequencies were assigned to these units. |
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The FM transmitter that the teacher wore around her neck. The wire
stand kept the microphone pointing better towards the teacher's mouth.
It also kept the microphone from picking up clothing sounds. |
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A close-up of the controls on the FM microphone. |
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The receiver units were housed in a special carrying
case, each of which held eight receivers. The bottom of the case doubled
as the charger. The transmitter unit was also charged up
by a charging cord from the case. |
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The carrying case showing two empty charging slots for the FM
receivers. |
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The carrying case included
the charging circuit for the receivers. A control knob set the
number of hours to be charged. Actually, you set it for the number of
hours you expected to use the system the next day. So if you expected to
use it for 5 hours in school, you set the knob to 5. That way the
batteries were completely run down by the end of the day, which
prevented them from developing a "memory" and not fully charging in the
future.
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The carry case with the lid on.
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