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TIA Presentation:TIA-1083

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-1083: Revision & The Future – Stephen Whitesell

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Meeting Attendees

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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– 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

• Hearing Loss Association of America (HLAA)

• Gallaudet RERC on Telecommunications Access

• Members of Congress

• National Association for Deaf

• U.S. Access Board• Federal Communications

Commission

TIA works with these organizations to support initiatives to help those with hearing loss:

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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 ConventionStudy 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.

– 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

Compliant products with these logos are currently widely available in the market.

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Compatible withHearing Aid T-Coil

TIA-1083

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TIA-1083-A

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

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 Signalfor Measurement of Desired Magnetic

Field

Borrowed verbatim from 47 CFR 68.316

-10 dBVoc from 900 ohm source applied directly to telephone

For typical 600 ohm telephone, the voltage divider action results in -18 dBV, or -15.8 dBm across the telephone terminals.

-10 dBVoc

900

600- 18 dBV

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Translation to Digital Test Signal

for Measurement of Desired Magnetic

Field 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 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

DEO DEO

Internet

ANA

DIG

IP

ANA

DIG

IP

PSTN

0 dBSLR = 8 RLR = 2

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Receive Implementations

DEO

6 dBD/AAnalogPhone

DigitalPhone

IPPhone

Analog Loop3 dB Avg

Digital Loop0 dB

IP Connection0 dB

SLR = 8

SLR = 8

RelativeLevel

Ref

+9 dB

+9 dB

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Future of TIA-1083

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Thank You

• Questions or Comments?

…Also, feel free to contact us:TIA DC Office

10 G Street, NE Suite 550Washington, DC 20002

(202) 346-3240