Provide audio or acoustic information, including any auditory feedback tones that are important for the use of the product, through at least one mode in enhanced auditory fashion (i.e., increased amplification, increased signal-to-noise ratio, or combination). For transmitted voice signals, provide a gain adjustable up to a minimum of 20 dB. For incremental volume control, provide at least one intermediate step of 12 dB of gain.
1. People who are hard of hearing but
not deaf can often use their hearing to access auditory information on a
product.
2. Strategies for addressing this
requirement may include the following:
a. Improve the signal to noise ratio by making the volume adjustable,
between 18-25 dB, increasing the maximum undistorted volume, and minimizing
background noise by such methods as better
coupling between the signal source and the user.
b. Alerting tones are most likely to be heard if they involve multiple tones, separated in frequency, which contrast with the
environment.
c. Occasionally, varying tones may be preferred for attracting
attention. If speech is used, it is best to test its intelligibility with
individuals who are hard of hearing to
maximize its clarity and ease of understanding. Provide the ability for the
user to have any messages repeated or to repeat
the message if no response is
received from the user.
d. For essential auditory information, the information might be
repeated and an acknowledgment from the user requested.
e. The intelligibility of the output can also be maximized by the location of the speakers and by keeping the speakers away from noise
sources. However, visual displays are
often more desirable than loud prompts or alerts, because the latter reduce
privacy and can annoy others unless the amplified signal is
isolated by means of a headphone, induction coupling, direct plug-in to
a hearing aid, or other methods.
f. The use of a telephone handset or earcup which can be held up to the ear can improve intelligibility without disturbing others in the area. If a handset or earcup is used, making it compatible with a hearing aid allows users to directly couple the auditory signal to their hearing aids. If the microphone in the handset is not being used, turning it off will also reduce the amount of background noise which the person hears in the earpiece. Providing a headphone jack also allows individuals to plug in headphones, induction loops, or amplifiers which they may use to hear better.
Volume
Control - All telephones, including cordless telephones, that are
manufactured in or imported into the United States after January 1, 2000, must
have volume control. Secure
telephones, telephones used with public mobile services and private radio
services are exempt from the FCC’s wireline rules, but are covered under the
Telecommunications Act of 1996.
On April 26, 1999, the FCC’s Common Carrier Bureau released a Public Notice outlining the various compliance dates to remind businesses of their obligations, and to assist in the successful implementation of the Commission’s rules.