Understanding Hearing Aid and Digital Wireless Cell Phone Compatibility
Cell phones produce radio frequency (RF) emissions that can result in interference noises heard by the hearing aid user. Cell phone manufacturers must now provide microphone (M) and telephone (T) immunity ratings for their phones to meet Federal Communication Commission (FCC) requirements for hearing aid compatibility.
Cell phone ratings should be visible on all hearing aid compatible cell phone packaging and in-store price cards. There are different technologies which then transmit within specific frequency ranges. Ratings are reported for the 800-950 MHz and 1600-2480 MHz frequency ranges relating to the range or band used by the wireless service provider. Some providers use GSM (e.g. T-Mobile) while others use CDMA (e.g. Verizon, Sprint) wireless digital technology. As of September 2006, each nationwide wireless carrier must offer its customers a select number of cell phone models which meet requirements for each transmission technology (i.e. CDMA, GSM, iDEN and TDMA). At least half of cell phones will need to meet requirements by February 2008.
Only those cell phones that meet a minimum rating of M3 or M4 (re: acoustic coupling) and T3 or T4 (re: telephone coupling) are labeled as meeting immunity requirements. The higher the "M" and/or "T" rating, the less likely the potential for interference.
Hearing aids can also be rated for immunity. While no hearing aid is totally immune from interference, some have more immunity to the RF interference than others. Like cell phones, the greater the “M” and/or “T” rating the better.
Cell phone and hearing aid ratings are combined to help identify which are more likely to provide a good listening experience for the user.
| Classification |
U Category Sum |
| Usable |
Hearing aid + telephone =4 |
| Normal |
Use Hearing aid + telephone =5 |
| Excellent Performance |
Hearing aid + telephone =6 |
From Audiology Association of America (AAA), 2003
Referring to the guide above, a hearing aid with an immunity rating, for example, of M3 + a cell phone with an immunity rating of M3 = 6 or “Normal Use”. Customers should contact their wireless telephone service provider regarding the form of technology used, immunity ratings and any additional information or necessary phone settings for optimum compatibility. Of greatest importance is the old adage “buyers beware”. It is recommended that the hearing aid user try the hearing aid compatible phone in the store before buying it.
Immunity Ratings of Widex Hearing Aids
Widex Integrated Signal Processing (ISP) hearing instruments such as Passion, Inteo, Aikia and Flash, offer excellent immunity (i.e. M4 and T4) and should provide normal if not excellent performance depending on the cell phone rating. All immunity ratings are published on each Widex digital product technical data sheet and are consistent with low interference levels and appropriate telephone coupling capabilities. Ratings for Widex ISP products are provided below.
Immunity Ratings for Widex ISP Hearing Aids
|
U Rating- Microphone |
U Rating- Telephone |
800- 950 MHz |
1.6- 2.0 Ghz |
800- 950 MHz |
1.6- 2.0 GHz |
PA-115 |
M4 |
M4 |
N/A |
N/A |
|
U Rating- Microphone |
U Rating- Telephone |
800- 950 MHz |
1.6- 2.0 Ghz |
800- 950 MHz |
1.6- 2.0 GHz |
>
IN-CIC |
M4 |
M4 |
N/A |
N/A |
IN-X |
M4 |
M4 |
T4 |
T4 |
IN-9 |
M4 |
M4 |
T4 |
T3 |
IN-9é |
M4 |
M4 |
T4 |
T3 |
IN-19 |
M4 |
M4 |
T4 |
T4 |
IN-m |
M4 |
M4 |
N/A |
N/A |
|
U Rating- Microphone |
U Rating- Telephone |
800- 950 MHz |
1.6- 2.0 Ghz |
800- 950 MHz |
1.6- 2.0 GHz |
>
AK-CIC |
M4 |
M4 |
N/A |
N/A |
AK-X |
M4 |
M4 |
T4 |
T4 |
AK-9 |
M4 |
M4 |
T4 |
T4 |
AK-9é |
M4 |
M4 |
T3 |
T3 |
AK-19 |
M4 |
M4 |
T3 |
T3 |
AK-m |
M4 |
M4 |
N/A |
N/A |
|
U Rating- Microphone |
U Rating- Telephone |
800- 950 MHz |
1.6- 2.0 Ghz |
800- 950 MHz |
1.6- 2.0 GHz |
>
FL-CIC |
M4 |
M4 |
N/A |
N/A |
FL-X |
M4 |
M4 |
T4 |
T4 |
FL-9 |
M4 |
M4 |
T4 |
T4 |
FL-9é |
M4 |
M4 |
T4 |
T4 |
FL-19 |
M4 |
M4 |
T4 |
T4 |
FL-m |
M4 |
M4 |
N/A |
N/A |
Immunity Ratings for Widex DSP Hearing Aids
|
U Rating- Microphone |
U Rating- Telephone |
800- 950 MHz |
1.6- 2.0 Ghz |
800- 950 MHz |
1.6- 2.0 GHz |
SD-CIC |
M4 |
M4 |
N/A |
N/A |
SD-X |
M3 |
M4 |
T2 |
T3 |
SD-9é |
M4 |
M4 |
T2 |
T2 |
SD-9M |
M4 |
M4 |
T3 |
T4 |
SD-19 |
M4 |
M3 |
T2 |
T1 |
|
U Rating- Microphone |
U Rating- Telephone |
800- 950 MHz |
1.6- 2.0 Ghz |
800- 950 MHz |
1.6- 2.0 GHz |
SV-CIC |
M4 |
M3 |
N/A |
N/A |
SV-X |
M4 |
M4 |
T3 |
T3 |
SV-XP |
M4 |
M4 |
T2 |
T2 |
SV-9 |
M4 |
M2 |
T2 |
T1 |
SV-9é |
M3 |
M3 |
T2 |
T2 |
SV-19 |
|
M1 |
T2 |
N/A |
SV-38 |
M4 |
M1 |
T3 |
N/A |
|
U Rating- Microphone |
U Rating- Telephone |
800- 950 MHz |
1.6- 2.0 Ghz |
800- 950 MHz |
1.6- 2.0 GHz |
BV-CIC |
M4 |
M4 |
N/A |
N/A |
BV-X |
M4 |
M4 |
T4 |
T2 |
BV-XP |
M4 |
M4 |
T4 |
T2 |
BV-8 |
M4 |
M3 |
T3 |
T2 |
BV-8é |
M4 |
M2 |
T4 |
T2 |
BV-9 |
M4 |
M4 |
T4 |
T1 |
BV-18 |
M3 |
M2 |
T3 |
T2 |
BV-19 |
M4 |
M3 |
T3 |
T2 |
BV-38 |
M4 |
M3 |
T3 |
T2 |
|
U Rating- Microphone |
U Rating- Telephone |
800- 950 MHz |
1.6- 2.0 Ghz |
800- 950 MHz |
1.6- 2.0 GHz |
B2-CIC |
M4 |
M4 |
N/A |
N/A |
B2-X |
M4 |
M4 |
T3 |
T2 |
BX-P |
M4 |
M3 |
T4 |
T1 |
B2 |
M4 |
M3 |
T2 |
T1 |
B12 |
M4 |
M3 |
T3 |
T1 |
B32 |
M4 |
M4 |
T4 |
T4 |
*Microphone (M) Telephone (T) immunity test rating depends on the frequency band used by the wireless service provider. Contact your wireless service provider regarding this and any additional information or necessary phone settings for optimum compatibility.
Note: Telephone rating is not applicable in the absence of a telecoil. The telecoil is not available in CIC, m-series models or Passion hearing instruments.
