In times past, many people with hearing aids had trouble using the telephone. It was necessary to hold the telephone earpiece close to the microphone in the hearing aid. But the hearing aid picked up a lot of stray noise, and sometimes produced squealing feedback.
The first technical fix was a special coil of wire in the hearing aid that couples electromagnetically to the earpiece or another coil in the telephone. Instead of the telephone receiver converting the incoming voice signal to sound, and the hearing aid microphone converting it back to electricity for amplification, the signal passes in electrical form directly from one coil to the other. This largely eliminates background noise and feedback, and gives far clearer reception. A telephone equipped with the right kind of coil is said to be “hearing aid compatible.”
But the technical solution ran into an economic problem. While people with hearing aids could easily put hearing aid compatible telephones in their homes, those telephones were scarce elsewhere. The institutions responsible for putting phones into places like hotels, workplaces, public libraries, etc., had little incentive to spend more for hearing aid compatible equipment.
This kind of stand-off rarely goes away without regulation. In 1988 Congress duly stepped in, and passed a statute instructing the FCC to address the problem. The next year the FCC launched a sequence of rules that required a specified fraction of the telephones accessible to the public to be hearing aid compatible. That fraction has gradually increased since. Today, hearing aid compatibility is required for every wireline telephone manufactured – or imported for use – in the United States, including cordless phones.
The initial rules exempted cellphones, which were not all that common anyway in 1988. But in 2003, with wireless phones well on the way to ubiquity, the FCC reversed course. It required manufacturers of wireless phones to make available a certain number or percentage of models that are hearing aid compatible.
By 2003, though, the vast preponderance of wireless phones were digital. Adding hearing aid compatibility to a digital cell phone is technically difficult, at least compared to a traditional wireline analog phone. Stray low-level signals from digital circuits in the phone tend to produce audible interference in the hearing aid, particularly with GSM phones used by AT&T and T-Mobile. Another problem is a simple shortage of space. A modern smartphone contains a lot of components: up to six two-way radios (for 3G and 4G data, 800 MHz and 1.9 GHz voice, Wi-Fi, and Bluetooth), receivers for GPS and sometimes FM, antennas, display, camera and flash, tilt sensors, microphone and speaker, processor and memory, and a battery. All of this fits into a case a little bigger than a playing card and less than half an inch thick. Designers understandably resist having to configure components to minimize interference to hearing aids.
Under the post-2003 FCC rules, a wireless phone has two separate ratings for hearing aid compatibility. The “T” rating, from one to four, measures the effectiveness of communications using a coil. The “M” rating, also from one to four, assesses interference when the hearing aid does not use a coil, but instead picks up sound from the telephone earpiece.
To complicate matters, the hearing aid itself also receives an “M” rating. This denotes the hearing aid’s ability to suppress incoming interference, including the stray signals from a wireless phone. An M1 rating indicates the least resistance to interference, and M4 the most. To determine whether a particular digital wireless telephone is likely to interfere with a particular hearing aid, one adds the M ratings of both devices. A sum of four or above means the combination is usable; a sum of six or greater predicts excellent performance.
The FCC requires manufacturers and wireless service providers to ensure that some, but not necessarily all, of the handsets they offer carry at least T3 and M3 ratings. Very approximately, about a third of a manufacturer’s handsets, and half of a nationwide carrier’s handsets, must meet the requirements. The hearing aid compatible handsets cannot all be “plain vanilla,” but must span a range of features and functionality. Carriers must allow customers to test compatibility with their own hearing aids in the store prior to purchase.
Manufacturers and wireless carriers alike – even companies like Circle-K and 7-Eleven that carry prepaid phone cards and cellphones – must file annual reports with the FCC that list their hearing aid compatible handsets. And somebody at the FCC reads the reports. A small regional carrier in Northwest Alaska recently agreed to write a check for $13,000 to settle a claim that it offered too few hearing aid compatible models. To its credit, though, the FCC has a proceeding underway to assess whether the rules are accomplishing their intended purpose.
The engineering procedures for arriving at T and M ratings are highly complex. The FCC has outsourced the details to the American National Standards Institute (ANSI), a non-profit organization that sets standards for everything from (literally) the threads on nuts and bolts to interconnections in the national energy grid. Instead of devoting many pages of the FCC rulebook to the technical specifics, the FCC simply cites to the relevant ANSI standard. Unfortunately, when ANSI updates its standards, as it does periodically, the FCC must update the references in its rules. That requires a full-dress rulemaking proceeding. One such is underway now, a 25-page Notice of Proposed Rulemaking that basically just adds a newer ANSI standard.
Updating to the new standard is important. It will improve testing procedures, and also expand the standard to cover frequencies (including the new 700 MHz band, which some wireless carriers have recently begun using to provide 4G data service) beyond basic cellphone bands. Without the update, new technology products soon expected on the market might be exempt from compatibility requirements. (The FCC allowed the iPhone to be exempt when it first appeared.) Issues in the rulemaking include a cut-off date after which the current standard may no longer be used, and whether manufacturers must apply one standard or the other, rather than cherry-picking parts of each.
Comments and reply comments on the ANSI update are due 30 and 45 days, respectively, after publication in the Federal Register, which has not yet occurred. We will post the due dates here when they are announced.