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Description / Abstract:
This standard applies to both wireless communications devices
(WDs) and hearing aids. It sets forth uniform methods of
measurement and parametric requirements for the electromagnetic and
operational compatibility of hearing aids used with WDs, including
cellular phones, personal communications service (PCS), and
Voice-over-Internet-Protocol devices, operating in the range of 698
MHz to 6 GHz.1 TIA-1083:2007 [B71] has become the
recognized standard for wireline communications devices, including
cordless telephones (cordless handsets with wireline-connected base
units). Ongoing communications between the TIA-1083 and ANSI C63.19
working groups have been maintained with the objective of
harmonizing the two standards to the maximum extent possible.
This standard is intended to apply to all types of hearing aids
with acoustic output, including, as examples, behind-the-ear (BTE),
in-the-ear (ITE), in-the-canal (ITC), and completely-in-the-canal
(CIC) types. Test methods are provided for acoustic (microphone
input) mode and tele-coil (T-Coil) hearing aid modes of
operation.
Users of this standard are cautioned to maintain the field
strength called for in various places in the document within the
limits for radio-frequency (RF) safety specified in IEEE Std
C95.1TM.2
Purpose
The purpose of this standard is to establish categories for
hearing aids and for WDs that can 1) indicate to health care
practitioners and hearing aid users which hearing aids are
compatible with which WDs, 2) provide tests that can be used to
assess the electromagnetic characteristics of hearing aids and WDs,
and 3) assign them to these categories. The various parameters
required in order to demonstrate compatibility are measured. The
design of the standard is such that when a hearing aid and a WD
achieve one of the categories specified, as measured by the
methodology of this standard, the indicated performance is
realized.
To provide for the usability of a hearing aid with a WD, several
factors must be coordinated, as follows:
— The field strength emitted by a WD must not exceed the RF
immunity of the hearing aid.
— The T-Coil, baseband H-field transmission of the WD must be
compatible with the T-Coil mode of the hearing aid.
— The electronic noise from the WD in the T-Coil band must not
degrade the reception quality to unacceptable levels.
Both the WD's RF and audio-band emissions are measured. Hence,
the following measurements are made for the WDs:
a) RF near-field, E-field emissions
b) T-Coil mode, magnetic signal strength in the audio band
c) T-Coil mode, magnetic noise in the audio band
d) T-Coil mode, magnetic signal frequency response in the audio
band
Corresponding to these quantities, the hearing aid is measured
for the following:
— RF immunity in microphone mode
— RF immunity in T-Coil mode
The hearing aid T-Coil reception characteristics are also
important when assuring the usability of the T-Coil mode. When
these characteristics are coordinated, the goals of this standard
are accomplished.
Two principal conditions expose hearing-aid–equipped users to
undesired RF electromagnetic disturbances. The far-field condition
corresponds to the type of field a hearing-aid–equipped bystander
would experience when adjacent to a WD user. The near-field
condition corresponds to the more intense fields that a hearingaid–
equipped user of a WD would experience. This standard assesses the
near-field or user condition.
This standard describes preferred test methods and test
facilities and, in some cases, alternative test methods and
facilities. If alternative test methods or facilities are employed,
every effort shall be made to establish correlation with the
preferred ones. Any deviation from the preferred test methods, as
set forth in this standard, shall be fully described in the test
report.
Wherever the word shall is used in this standard, it
indicates something mandatory. The word should indicates
something that is advisory. The word may indicates an
option, which is at the discretion of the test engineer.
1 The current version of this standard provides
detailed procedures up to 3 GHz, although the scope has been
expanded up to 6 GHz. The guidance provided goes as far as
well-researched methods are available and covers the primary bands
relative to this issue.
2 For information on references, see Clause 2.