- 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 µW 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