LG Ally User Manual page 285

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 best use.
with the particular wireless phone. "Normal usage" in this context
is defined as a signal quality that's acceptable for normal
operation.
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.
When you're talking on a cell phone, it's recommended that you
turn the BT (Bluetooth) mode off for HAC.
For information about hearing aids and digital wireless phones
Wireless Phones and Hearing Aid Accessibility
http://www.accesswireless.org/hearingaid/
FCC Hearing Aid Compatibility and Volume Control
http://www.fcc.gov/cgb/consumerfacts/hac_wireless.html
In the example to the left, 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
Safety
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