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Dimensions (mm)
6 × 12 × 2
The magnitude of the complex impedance at 1 kHz is expressed in
ohms. As of an impedance for a receiver, we normally offer a 150-
ohm impedance, but will manufacture 300-ohm and other impedances
on demand.
Input power
When calculating input power it is assumed the impedance is
resistive, therefore,
where Z is the impedance at 1 kHz in ohms
E is the input voltage in volts
E2
P 103 in mW or 106 in W Z
Output Sound Pressure Level
As a method of measuring a telephone handset, we define the output
pressure level at 1000 Hz when an earpiece is attached to the
artificial ear specified in IEC318, and a voltage of 60 mV is applied
across the receiver terminals.
Please note that data comparison with those of other companies is
not valid because there are many differences in setting references
and input conditions, although the measuring methods of other
companies are almost similar to our method.
GENERATOR EAR CAP ACOUSTIC COUPLERFrom August 16th 1991 US FCC regulations required that all telephones
in public places shall be hearing aid compatible.
HAC receivers incorporate an additional coil, which produces a
magnetic field that couples to the hearing aid pick-up coil.
The AC magnetic field generated conforms to EIAR S-0504.
Leakage Measuring Evaluation
Traditionally, the performance of telephone receivers was measured
in a closed loop using the artificial ear specified in IEC 318. This
approach did not pose any serious problems in the past because
there were only a few types of telephone handsets available on the
market. In recent years, however, a variety of new types of telephones
such as cordless, portable and cellular telephones, have
entered the market one after another, and they come equipped with
various types of handsets. In the face of these new circumferences,
more and more manufactures are trying to adopt the so-called
open measurement method, in addition to the conventional closed
loop method. This is because they believe that more emphasis
should be put on auditory feeling in the working environment. Hosiden
has also decided to adopt the open measurement me