Bell Atlantic Mobile and Lucent Technologies Collaborate on
First-Ever Digital Cellular Service for Hearing and Speech Impaired
JANUARY 26, 2000
MURRAY HILL, N. J. - People with speech or hearing disabilities will be
able to make digital cellular phone calls - including 911 emergency calls -
- using text-telephone (TTY) devices plugged into wireless telephone
handsets, thanks to the Bell Atlantic Mobile unit of Bell Atlantic
Corporation (NYSE:BEL) and Bell Labs, the research and development
arm of Lucent Technologies (NYSE:LU).
Using innovative software from Bell Labs, Bell Atlantic Mobile plans to be
first in the world to make digital wireless systems compatible with TTY
devices, using the same path used for voice transmission. The carrier
plans to introduce the new service in the second half of next year with the
service initially available through Bell Atlantic Mobile's direct sales
The innovation pioneered by Bell Labs researchers was prompted by Bell
Atlantic Mobile's priority in meeting the needs of speech and hearing-
impaired customers, especially in emergency situations. Lucent is
informing the Federal Communications Commission (FCC) and industry
organizations that it is making the patents and technology available
royalty-free to wireless service providers and manufacturers serving TTY
customers, subject to certain conditions.
"We're going to bring the benefits of digital wireless service to a
large segment of the population that up until now couldn't use this state-
of-the-art technology" said Ted Hoffman, vice president of
Technology Development for Bell Atlantic Mobile. "In addition, this
successful collaboration benefits other wireless carriers' customers."
The FCC has mandated that wireless service carriers provide TTY users
access to 911 emergency services. Carriers deploying digital wireless
systems have so far been unable to meet the FCC requirement, however,
because existing digital wireless systems cannot accurately pass the
specially encoded audio tones produced by TTY devices.
Lucent's solution, developed by Steven Benno and Michael Recchione, of the Bell Labs
Speech and Audio Processing Technologies group, offers TTY users essentially error-
free digital transmission, even in areas with extremely poor reception. The technology
involves upgrading software both in the network and in the digital handset, yet retains
compatibility with existing digital wireless network standards.
The Telecommunications Industry Association (TIA) has adopted the Bell
Labs solution as a TTY solution that is compatible with the ANSI-41
standard for code-division and time-division multiple-access (CDMA and
TDMA) wireless systems.
"I can't think of a better example of cutting-edge communications
research being used to help people," said Ed Hall, co-chair of the
Cellular Telecommunications Industry Association's (CTIA) TTY Industry
Forum. "We're extremely pleased that Lucent devoted its energies
to such an important innovation for hearing- and speech-impaired
Digital wireless transmissions inherently contain errors, but error
correction techniques can mitigate the problem by reconstructing speech
to keep it intelligible on the receiving end. However, digital networks are
less forgiving in the case of the tones generated by TTY devices, and the
transmission errors can cause characters to be missed or changed on the
receiving end, resulting in unintelligible messages.
Lucent's solution to this problem is to detect the TTY characters being sent and to
repeatedly transmit those characters to the receiving end. The repetition allows the
receiving end to correctly regenerate the tones corresponding to those characters despite
Unlike other techniques, Lucent's solution treats TTY calls as data
transmissions that also permit voice conversation over the same
connection. Typically, people with speech impediments and hearing-
impaired people who can speak require TTY capability in one direction
and speech transmission in the other direction. While data-only calls
have a built-in capability for error correction, they do not allow a TTY user
to switch between voice and TTY. Lucent's method treats TTY calls the
same as voice calls -- a feature called voice carryover/hearing carryover -
that cannot currently be supported by treating TTY as a data call.
Bell Atlantic Mobile owns and operates the largest wireless network in the
East and systems in the Southwest, covering 216,000 square miles, and
the largest chain of retail outlets devoted exclusively to wireless voice,
data and paging. Based in Bedminster, NJ, Bell Atlantic Mobile has 7.3
million customers and 8,800 employees from Maine to Georgia and,
through a separate subsidiary in the Southwest. Through its
"Wireless at Work..." community service program, the
company uses its technology to help individuals and communities
improve security and emergency communications. Bell Atlantic Mobile's
parent, Bell Atlantic Corporation (NYSE:BEL) is one of the world's largest
wireless communications companies, with domestic operations in 25
states and international investments in Mexico, Europe and the Pacific
Rim. For more information on Bell Atlantic Mobile visit:
http://www.bam.com ; on global operations visit: http://www.bellatlantic.com/worldwide.
Lucent Technologies, headquartered in Murray Hill, N. J., designs,
and delivers a wide range of public and private networks, communications
systems and software, data networking systems, business telephone
systems, and microelectronics components. Bell Labs is the research and
development arm for the company. For more information on Lucent
Technologies, visit its Web site at http://www.lucent.com.