FCC Record, Volume 27, No. 5, Pages 3728 to 4696, April 9 - April 27, 2012 Page: 3,733
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2. The standard that we adopt today was developed through a voluntary, consensus-driven
approach and is broadly supported by both industry and consumer groups. We extend our appreciation
for the efforts of the many parties involved in developing this standard. We strongly encourage all parties
to continue their efforts to refine and develop standards applicable to new telephone technologies that
may create potential for interference with hearing aids.
3. To ensure that a selection of digital wireless handset models is available to consumers
with hearing loss, the Commission's rules require both manufacturers and service providers to meet
defined benchmarks for deploying hearing aid-compatible wireless phones. Specifically, manufacturers
and service providers are required to offer minimum numbers or percentages of handset models that meet
technical standards for compatibility with hearing aids operating in both acoustic coupling and inductive
coupling modes.' These benchmarks apply separately to each air interface for which the manufacturer or
service provider offers handsets.2
4. To define and measure the hearing aid compatibility of handsets, the Commission's rules
reference the 2007 revision of American National Standards Institute (ANSI) technical standard C63.19
(the "2007 ANSI Standard"), formulated by the Accredited Standards Committee C63* - Electromagnetic
Compatibility (ASC C631).3 A handset is considered hearing aid-compatible for acoustic coupling if it
meets a rating of at least M3 under the 2007 ANSI Standard.4 A handset is considered hearing aid-
compatible for inductive coupling if it meets a rating of at least T3.5 The 2007 ANSI Standard specifies
testing procedures for determining the M-rating and T-rating of digital wireless handsets that operate over
the air interfaces that, at the time it was promulgated, were commonly used for wireless services in the
800-950 MHz and 1.6-2.5 GHz bands.
' 47 C.F.R. 20.19(c), (d). Hearing aids operating in acoustic coupling mode receive through a microphone and
then amplify all sounds surrounding the user, including both desired sounds, such as a telephone's audio signal, and
unwanted ambient noise. Hearing aids operating in inductive coupling mode turn off their microphone to avoid
amplifying unwanted ambient noise, instead using a telecoil to receive only audio signal-based magnetic fields
generated by inductive coupling-capable telephones. The hearing aid converts these fields back to sound or a signal
appropriate for cochlear implant users.
2Id. The term air interface refers to the technology that ensures compatibility between mobile radio service
equipment, such as handsets, and a service provider's base stations. To further ensure that the handsets available to
consumers with hearing loss include the newest and most advanced technologies, manufacturers are required to
partially refresh their offerings of hearing aid-compatible phones each year, and service providers must offer a range
of hearing aid-compatible phones with differing levels of functionality. Id. 20.19(cX1 )(ii), (c)(4)(ii), (d)(4)(ii).
3 47 C.F.R. 20.19(b)(l)(ii), (b)(2)(ii).
4 47 C.F.R. 20.19(b)(1)(ii). To use a digital wireless phone with a hearing aid or cochlear implant in acoustic
coupling mode, RF interference and other electromagnetic interference from the wireless phone must be controlled.
ANSI C63.19 specifies ratings for digital wireless phones, MI through M4, based on their RF emission levels, with
MI being the highest emissions and M4 the lowest emissions. The standard also provides a methodology for rating
hearing aids from M I to M4 based on their immunity to interference, with MI being the least immune and M4 the
most immune. To determine whether a particular digital wireless phone is likely to interfere with a particular
hearing aid, the immunity rating of the hearing aid is added to the emissions rating of the wireless phone. A sum of
4 indicates that the wireless phone will be usable; a sum of 5 indicates that the wireless phone will provide normal
use; and a sum of 6 or greater indicates that the wireless phone will provide excellent performance with that hearing
aid. See Accredited Standards Committee C635 - Electromagnetic Compatibility, American National Standard
Methods of Measureent of Compatibility between Wireless Communications Devices and Hearing Aids, ANSI
C63.19-2007 (June 8, 2007) at 5.
S47 C.F.R. 20.19(bX2)(ii). Handsets are rated from TI to T4 for inductive coupling capability in a similar manner
to the M-ratings.
Federal Communications Commission
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United States. Federal Communications Commission. FCC Record, Volume 27, No. 5, Pages 3728 to 4696, April 9 - April 27, 2012, book, April 2012; Washington D.C.. (digital.library.unt.edu/ark:/67531/metadc102307/m1/22/: accessed November 23, 2017), University of North Texas Libraries, Digital Library, digital.library.unt.edu; crediting UNT Libraries Government Documents Department.