Transcript Slide 1

TIA Presentation:
TIA-1083-A
TIA
User Premise Equipment Division
June 4, 2009
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Agenda
Overview of TIA – Rebecca Schwartz
TIA -1083: History, TIA’s Role & Accomplishments –
Al Baum
TIA-1083A: Revision & The Future – Stephen
Whitesell
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Meeting Attendees
Al Baum, Engineering Manager, Uniden America Corporation
Fred Lucas, Principal, FAL Associates
Paul Schomburg, Sr. Manager, Government & Public Affairs, Panasonic
Corporation of North America
Stephen Whitesell, Sr. Technical Consultant, Standards, Regulatory and
Intellectual Property Matters, VTech Communications
Rebecca Schwartz, Director, Regulatory and Government Affairs, TIA
Patrick Sullivan, Director, Technical and Government Affairs, TIA
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Telecommunications Industry
Association
A leading Standards Developing Organization (SDO)
accredited by American National Standards Institute (ANSI).
Represents the global information and communications
technology (ICT) industry through
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Standards development
Advocacy
Business opportunities
Market intelligence
World-wide environmental regulatory compliance.
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Telecommunications Industry
Association
Supports the development of innovative technology to
facilitate access to information by all Americans, including
those with disabilities.
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TIA Works to Help People
with Hearing Loss
TIA works with these organizations to support
initiatives to help those with hearing loss:
Hearing Loss Association
of America (HLAA)
National Association for
Deaf
Gallaudet RERC on
Telecommunications
Access
U.S. Access Board
Federal Communications
Commission
Members of Congress
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Recent Policy Activities
Policy Activities in 2008-2009 Include:
– TIA 10th Annual Spring Policy Summit addressed
accessibility under the new Administration
– Working with Congressional staff on Rep. Markey’s
accessibility bill
– TIA filed Accessibility Initiatives with President
Obama’s Transition Team
– TIA co-hosted Accessibility Technology Fair on Capitol
Hill
– Coordination with the Assistive Technology (AT)
industry
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Review of the Development
of TIA-1083
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Consumer Complaints
In 2004, telephone manufacturers began to receive customer
complaints regarding hearing aid interference problems with
digital cordless telephones.
Specifically consumers were hearing a buzz noise when using
digital cordless telephones with hearing aids and cochlear
implants when set to T-Coil mode.
There were no reports of the buzz noise from analog cordless
telephones.
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Industry Response
At the August 2004 meeting of TIA Subcommittee TR41.3 a
Gallaudet University presentation on the subject was discussed
along with possible causes for the reported interference.
The consensus belief was that, due to the low RF power levels
used by cordless phones, the source of the reported
interference was probably magnetic.
Further work towards confirming this belief and developing a
testing method to characterize the magnetic interference was
conducted during the remainder of 2004 and first half of 2005.
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Industry Response
First, the complaint phones were tested for compliance with the
FCC Part 68.316 HAC regulations. The test results confirmed
that all of the phones were compliant.
Next, the complaint phones were tested with hearing aids
obtained from and programmed by Gallaudet University. This
testing confirmed that digital spread spectrum cordless
telephones were indeed causing interference to hearing aids.
(This testing also confirmed that analog cordless telephones did
not cause interference.)
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Why was this happening?
Analysis of the noise characteristics indicated that the source
of the noise was the Time Division Duplexing (TDD) employed
by the Digital Spread Spectrum (DSS) cordless phones to
enable them to transmit and receive on the same frequency.
This turning on and off of the transmitter at a very rapid rate
resulted in large changes in battery current which in turn
caused large changes in the magnetic field produced by the
wiring in the handset.
This magnetic pulsing was being picked up by the T-Coil in the
hearing aid and heard as a loud buzzing noise by the wearer.
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HLAA Studies
2005 HLAA National Convention
Study conducted by Linda Kozma-Spytek of the
Rehabilitation Engineering and Research Center (RERC) on
Telecommunications Access and the Technology Access
Program at Gallaudet University.
Volunteers from among the HLAA Convention attendees
tested a group of phones and rated their performance.
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Loudness
Percent Words Understood
Interference
Usability
“Would you buy a phone with this level of interference?”
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HLAA Studies
2006 HLAA National Convention
Study conducted by Gallaudet University, Etymotic
Research and Motorola.
Volunteers from among the HLAA attendees participated in
this study and helped to answer the question:
“How much noise is too much noise?”
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TIA Completes Development
of New Standard
Results from the two HLAA Studies were compared with lab
measurements by TIA member companies.
Performance Requirements were established
Compliant phones were tested by wearers of hearing aids and
cochlear implants with good results.
ANSI/TIA-1083 “Handset Magnetic Measurement Procedures
and Performance Requirements” was published in March 2007.
Official “TIA-1083” logo was developed and licensed by TIA to
manufacturers for display on the packaging of compliant
products.
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Official TIA-1083 Logo
Compatible with
Hearing Aid T-Coil
Compatible with
Hearing Aid T-Coil
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TIA-1083
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TIA-1083
Compliant products with these logos are widely available in
the market.
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TIA-1083-A REVISION OVERVIEW
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TIA-1083-A Differences
Minimal changes for telephones with analog interfaces
that were covered by TIA-1083.
Transverse performance requirements that had an effective date
24 months after March 2007 publication of TIA-1083 are now
mandatory for compliance with the standard.
Frequency response template now applies to transverse
magnetic field as well as to perpendicular magnetic field.
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TIA-1083-A Differences
Main purpose was to add requirements for wireline
products with digital interfaces such as VoIP telephones,
softphones running on personal computers, etc.
Goal was identical performance requirements for all telephones.
Since magnetic noise sources are internal to the telephone
handset, the same test procedures should apply.
Specifying digital input signal equivalent to analog signal being
used for measuring desired magnetic field was the challenge.
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Analog Test Signal
for Measuring Desired Magnetic Field
Borrowed verbatim from 47 CFR 68.316
-10 dBVoc from 900 ohm source applied directly to telephone
900
-10 dBVoc
- 18 dBV
600
For typical 600 ohm telephone, the voltage divider action
results in -18 dBV, or -15.8 dBm across the telephone
terminals.
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Digital Test Signal
for Measuring Desired Magnetic Field
The analog test signal needs to be translated to an
equivalent digital test signal.
Telephones with digital interfaces typically encounter a 9 dB
higher signal level applied to their terminals than telephones
with analog interfaces.
So TIA-1083-A specifies a -7 dBm signal for measuring the
desired magnetic field field produced by a telephone with a
digital interface.
-15.8 dBm + 9 dB  -7 dBm
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Why 9 dB Difference?
Transmission Plans and Standards
The Public Switched Telephone Network is all digital from end
office to end office with no loss between end offices.
Likewise calls placed via the Internet experience no loss between
where they enter the Internet and where they leave it.
Thus, the loudness of a telephone call is determined by the
acoustic-to-electrical conversion efficiency at the send end and
the electrical-to-acoustic conversion efficiency at the receive end.
However, a 6 dB loss pad used in the receive direction for analog
lines at the Digital End Office (DEO) to control echo must be taken
into account.
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Transmission Plans
SLR = 8
0 dB
RLR = 2
ANA
ANA
PSTN
DEO
DEO
DIG
IP
DIG
Internet
IP
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Receive Implementations
Relative
Level
D/A
SLR = 8
SLR = 8
6 dB
Analog Loop
3 dB Avg
Ref
Analog
Phone
Digital Loop
0 dB
+9 dB
Digital
Phone
IP Connection
0 dB
+9 dB
IP
Phone
DEO
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Future of TIA-1083
Devices with a digital interface that do not support G.711 or
L16-256 codecs are likely to require test signals other than sine
waves and are under study for inclusion in an addendum or
future revision of this standard.
An alternative to the A-weighting function that is claimed to
provide better subjective correlation over a wider range of
interfering noise types is also under study for possible inclusion
in an addendum or future revision of this standard.
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Thank You
Questions or Comments?
…Also, feel free to contact us:
TIA DC Office
10 G Street, NE Suite 550
Washington, DC 20002
(202) 346-3240
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