User's Manual

phones that are not labeled. T4 is the better/ higher of the two

ratings.

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.

In the example illustrated above, 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’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/Home.aspx

FCC Hearing Aid Compatibility and Volume Control

http://www.fcc.gov/cgb/consumerfacts/hac_wireless.htm