User's Manual

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are more immune than others to this interference noise, and phones also vary in the amount of
interference they generate. The wireless telephone industry has developed a rating system for
wireless phones, to assist hearing device users find phones that may be compatible with their
hearing devices. Not all phones have been rated. Phones that are rated have the rating on their box
or a label located on the box. The ratings are not guarantees. Results will vary depending on the
user’s hearing device and hearing loss. If your hearing device happens to be vulnerable to
interference, you may not be able to use a rated phone successfully. Trying out the phone with your
hearing device is the best way to evaluate it for your personal needs.
M-Ratings: Phones rated M3 or M4 meet FCC requirements and are likely to generate less
interference to hearing devices than phones that are not rated. M4 is the better/higher of the two
ratings. Your device is rated M3.
T-Ratings: Phones rated T3 or T4 meet FCC requirements and are likely to be more usable with
a hearing aid’s telecoil than phones that are not rated.
T4 is the better/higher of the two ratings. Your device is rated T3.
Please power off the Bluetooth function while using hearing aid devices with your Chaser. Hearing
devices may also be rated. Your hearing device manufacturer or hearing health professional may
help you find this rating. Higher ratings mean that the hearing device is relatively immune to
interference noise.
The hearing aid and wireless phone rating values are then added together. A sum of 5 is
considered acceptable for normal use. A sum of 6 is considered for better use. A sum of 8 is
considered for best use. In the above example, if a hearing aid meets the M2 level rating and the
wireless phone meets the M3 level rating, the sum of the two values equal M5. This should provide
the hearing aid user with “normal usage” while using their hearing aid with the particular wireless
phone. “Normal usage” in this context is defined as a signal quality that is acceptable for normal
operation.
This methodology applies equally for T ratings. The M mark is intended to be synonymous with the
U mark. The T mark is intended to be synonymous with the UT mark. The M and T marks are
recommended by the Alliance for Telecommunications Industries Solutions (ATIS). The U and UT
marks are referenced in Section 20.19 of the FCC Rules. The HAC rating and measurement
procedure are described in the American National Standards Institute (ANSI) C63.19 standard.
For information about hearing aids and digital wireless phones FCC Hearing Aid Compatibility and
Volume Control: http://www.fcc.gov/cgb/dro/hearing.html
Gallaudet University, RERC:
https://fjallfoss.fcc.gov/oetcf/eas/reports/GenericSearch.cfm