SHHH Research Symposium
Access to Telecommunications
Judy Harkins of Gallaudet University presented a synopsis of recent
work at Gallaudet's Rehabilitation Engineering Research Center (RERC) on
Telecommunications Access, which is working on a cooperative program
with the Trace Center at the University of Wisconsin. RERC's goal is to
improve telecommunications access for all people with disabilities, so
hearing loss is only one of their areas of exploration.
One of their goals is to provide built-in access, which means that
people without disabilities use the same equipment as those with
disabilities. In many cases this means providing compatibility with
special devices used by people with disabilities.
Six years ago SHHH identified that changes to wireless phones would
make it harder for people with hearing loss to use them. The particular
change was the transition from analog technology to digital technology.
SHHH petitioned the FCC to address this issue, and the FCC directed the
RERC to access the situation. One of the problems at that time was that
virtually all of the available telecommunications experts worked for the
telecommunications industry, so that independent analysis would be
difficult.
RERC's first action was to evaluate the extent of the problem. They
tested 57 people and found that most of them suffered interference from
the new digital wireless phones when they tried to use the phones. The
researchers were pleasantly surprised to find that this was the only
time they experienced interference; they had originally been concerned
that the use of a digital wireless phone by another person in close
proximity to a hearing aid could cause interference in the hearing aid.
Their second study was to determine the required level of speech
signal above the interference to ensure understandability. They
determined that a speech signal 30 db above the interference enabled
about 90% of people to understand. However, people tended to rate the
phone as "not highly usable" if the interference was audible
at all.
Another issue was the lack of standards in the industry. A standards
group had been established, but had not yet created standards. The RERC
advocated the creation of two standards - one to classify phones for
susceptibility to causing interference in hearing aids, and the other to
classify hearing aids for susceptibility to interference from digital
wireless phones.
RERC is now doing clinical investigations with a small number of
users and a large number of phones and accessories, including neckloops,
HATIS devices, CHAAMP, and the Plantronics headset. The idea of many of
these accessories is to get the phone away from the hearing aid. Despite
the fact that this strategy seems to work, most people in the study
group don't consider this a long-term solution; they prefer to hold the
phone to their ear.
This study also reveals that all of the participants hear better on
an analog phone than on a digital phone, even if there is no
interference on the digital phone. This means that people with hearing
loss lose usability when moving to a digital phone, even if there is no
interference from that phone.
The Hearing Aid Compatibility Act of 1988 provided that all wired
phones must be hearing compatible, but that act gave an exemption to
wireless phones. The FCC is now considering lifting that exemption.
In 1996 the FCC ordered the wireless industry to make their phones
TTY-compatible. This rule was initially to take effect in 1997. However,
the wireless digital phone system is complex, involving a lot of
different equipment from many different manufacturers. So the FCC
provided extensions to the 1997 date, with the last one expiring June
30, 2002.
One goal of the RERC is to predict the next "Whammy". This
is hard, because they don't know which technologies will be included in
future telecommunications equipment. But it is a real advantage to be
able to predict future technology deployments and head off those that
reduce access before they become part of the equipment.
The folks at RERC think that the next issue will be digital voice
transmission on wired lines. Voice has historically been transmitted
using analog signals, but this technology requires a lot of bandwidth.
The telecommunications industry is moving to digital voice transmission
to reduce bandwidth requirements. One result of this transition is that
the received voice signal will be less clear than it would be using
analog transmission. This may or may not be an issue to people with
hearing loss, but the FCC won't know, because they are only testing this
technology on people with normal hearing. The RERC is starting a project
to evaluate the effect of this technology on people with hearing loss.
One ongoing problem for people with hearing loss is the use of voice
menus and voice mail. This is an example of a technology that
"snuck up" on the hearing loss community and is now firmly
entrenched. These issues were not anticipated before the investment was
made in this technology, so now our only option is to try to modify the
existing design. We have an industry forum looking into this, but it
would have been a lot easier to get access built in from the beginning.
Q: You didn't address what the hearing aid industry is doing about
electromagnetic interference. Do you know what is going on here?
A: That really isn't within my area of expertise. I do know that some
hearing aid companies are working on this, but I don't have any details.
Q: How about compatibility between digital wireless phones and
cochlear implants (CIs)?
A: I don't know of any studies in this area, but I hear that many CI
users are able to use digital wireless phones.
Q: You mentioned a July 1 deadline for digital wireless phones to be
TTY compatible. Can you elaborate?
A: I expect the first six months to be bumpy. It may be that not all
parts of all networks will initially be compatible. People must buy new
phones and new TTYs, and no one has checked all the combinations, so I
expect normal startup problems.
