User Guide
130 Health & Safety
Health & Safety
T-Ratings: Mobile devices rated T3 or T4 meet FCC requirements and are likely to generate less interference to hearing devices
than mobile devices that are not labeled. T4 is the better/higher of the two ratings. T-ratings refer to enabling inductive cou-
pling with hearing aids operating in telecoil mode.
Hearing devices may also be rated. Your hearing aid manufacturer or hearing health professional may help you nd this rating.
Higher ratings mean that the hearing device is relatively immune to interference noise.
Under the current industry standard, American National Standards Institute (ANSI) C63.19, the hearing aid and wireless mobile
device rating values are added together to indicate how usable they are together. For example, if a hearing aid meets the M2
level rating and the wireless mobile device meets the M3 level rating, the sum of the two values equals M5.
Under the standard, this should provide the hearing aid user with normal use while using the hearing aid with the particular
wireless mobile device. A sum of 6 or more would indicate excellent performance.
However, these are not guarantees that all users will be satised. T ratings work similarly.
M3 + M2 = 5
T3 + T2 = 5