Dolphin CT50 Mobile Computer with Windows 10 IoT Mobile Enterprise User Guide
Hearing Aid Compatibility (HAC)
The standard for compatibility of digital wireless devices with hearing
aids is set forth in American National Standards Institute (ANSI)
standard C63.19. ANSI C63.19 contains these two sets of standards:
An "M" rating from M1 to M4 for reduced radio frequency (RF)
interference to enable acoustic coupling with hearing aids that do not
operate in t-coil mode.
A "T" rating from T1 to T4 to enable inductive coupling with hearing
aids operating in t-coil mode.
A digital wireless handset is considered hearing aid compatible for
acoustic coupling if it meets at least an "M3" rating under the ANSI
standard. A digital wireless handset is considered hearing aid
compatible for inductive coupling if it meets at least a "T3" rating under
the ANSI standard
M-Ratings: Devices rated M3 or M4 meet FCC requirements and are
likely to generate less interference with hearing devices than devices
that are not labeled. M4 is the superior/higher of the two ratings.
T-Ratings: Devices rated T3 or T4 meet FCC requirements and are likely
to be more usable with a hearing device's t-coil than unrated devices. T4
is the superior/higher of the two ratings.
These ratings are not guaranteed. Results will vary depending on the
level of immunity of your hearing device and the degree of your hearing
loss. If your hearing device happens to be vulnerable to interference, you
may not be able to use a rated device successfully. Trying out the device
with your hearing device is the best way to evaluate it for your personal
When some wireless devices are used near some hearing devices such
as hearing aids and implants, users may detect a buzzing or humming
noise. Some hearing devices are more immune than others to this
interference noise. Wireless devices may also vary in the amount of
interference they generate. The more immune the hearing aid device is,
the less likely one is to experience interference noise from the wireless
Hearing aid devices may also be rated. Adding the ratings of the hearing
aid and the device can predict the usability of the two devices together:
Any combined rating equal to or greater than six offers the best use.
Any combined rating equal to five is considered normal use.