1. Cordless Telephones and Hearing Aids A Presentation on the Work of TIA TR-41.3 to the ATIS HAC Incubator Group August 23, 2005 TR41.3-05-11-003

2. 2 Ancient History  1982 – Telecommunications for the Disabled Act requires “essential” telephones to be usable by persons with hearing aids  1983 – TR-41.3 creates EIA RS-504 Axial and radial field intensity Axial frequency response  1984 – FCC adopts RS-504 into Part 68.316  1988 – Hearing Aid Compatibility Act requires virtually all wireline telephones to provide magnetic coupling

3. 3 Recent History  4/2004 – Informal FCC Complaints begin Digital cordless telephones Industry wide  6/2004 – TIA User Premises Equipment Division (UPED) forms Hearing Aid Compatibility (HAC) Task Force  8/2004 – TR-41.3 begins work to understand and characterize cause of digital cordless telephone interference with hearing aids  10/2004 – UPED meets with FCC and Self Help for Hard of Hearing People (SHHH) to inform them of TIA activities

4. 4 Recent History (cont)  5/2005 – TR-41.3 completes preliminary work and launches SP-3-0219, Measurement Procedures and Performance Requirements for Handset Generated In-Band Magnetic Noise (to become TIA-1083)  6/2005 – SHHH holds annual Convention in Washington, DC Gallaudet subjective study involving 32 hearing aid users and 8 digital cordless telephones TIA Member Companies show products intended to provide a solution

5. 5 Gallaudet SHHH Study  32 subjects who normally use a hearing aid when talking on the telephone 22 women and 10 men with ages from 43 to 79 12 reported moderate to moderately severe hearing loss, 18 reported severe or profound hearing loss, and 2 were not sure 27 used T-coil coupling and 5 used acoustic coupling  8 digital cordless telephones 5 off-the-shelf models and 3 potential solution models 4 operating at 2.4 GHz and 4 operating at 5.8 GHz 5 were frequency hoppers and 3 were direct sequence  2500 set included in study for baseline reference

6. 6 Gallaudet SHHH Study (cont)  Subjects asked to rate Loudness (1-7, inaudible to too loud) Percent words understood (1-5, 80%) Interference (0-5, none to unbearable) Usability (1-4, highly usable to not usable)  Subjects also asked to provide a yes or no answer as to whether, based on the interference they perceived, they would purchase the phone  Study funded under Grant No. H133E040013 from the National Institute on Disability and Rehabilitation Research

7. 7 Magnetic or RF Interference?

8. 8 Round Robin Measurements  SHHH study sets measured by 3 TR-41.3 members Desired magnetic field axial signal level and frequency response using full band integrator as defined in draft revision of C63.19 Undesired magnetic field axial signal level and frequency response using half band integrator as defined in draft revision of C63.19.  Compared results for following metrics: AFI (1 kHz) – desired axial field intensity at 1 kHz A-Weighted Noise – undesired magnetic field (half band, A wtd) Signal Quality – AFI(1 kHz) minus A-Weighted Noise Highest SFI – field strength of highest amplitude noise component Magnetic SFI – A-Weighted Noise minus Highest SFI Signal-to-Highest SFI Ratio – AFI(1 kHz) minus Highest SFI

9. 9 T-Coil Coupling Findings  Subjective Interference rating correlates best with A-Weighted Noise and Highest SFI measures  Interference rating also shows correlation to Signal Quality and Signal-to-Highest SFI Ratio measures  Slightly lower correlation of Purchase question and Usability rating to objective measures  Poor correlation of Loudness and Percent Words ratings to any objective measures  Poor correlation of AFI (1 kHz) and Magnetic SFI to any subjective ratings

10. 10 Current Status  Continuing to analyze Gallaudet SHHH subjective study data and objective measurements on same cordless phones by labs of 3 TR-41.3 members  Creating first draft of SP-3-0219 (to be TIA 1083)  Targeting committee ballot after 11/2005 meeting and industry ballot after 2/2006 meeting

11. 11 SP-3-0219 Draft Direction  Addressing magnetic interference All complaints seem to be related to T-coil use RF power levels lower than for cell phones Supported by SHHH study results  Relatively simple measurement procedure Connect the probe coil normally used for Part 68 testing to a spectrum analyzer instead of a narrow-band tracking analyzer Borrow the half-band integrator and A-weighting concepts from revision of C63.19 (Draft 3.1, October 7, 2004)  Set performance criteria to obtain high percentage of “Not Annoying” and “Highly Usable” ratings.

12. 12 Further Information  Documentation available on TR-41.3 FTP site: ftp.tiaonline.org/tr-41/tr41.3/Public Publicly available (anonymous FTP) Arranged in folders organized by meeting date Alternative browser access (no password required)  Next TR-41 meeting is week of November 7-11, 2005 in Santa Fe, NM TR-41.3 will meet on Thursday afternoon Anyone may attend one meeting as a guest Additional information available on TR-41 web page: www.tiaonline.org/standards/sfg/tr-41

13. 13 Contacts  TR-41.3 Chair is James Bress of AST Technologies (jrbress@asttechlabs.com)  SP-3-0219 Document Editor is Al Baum of Uniden (abaum@uniden.com)  TR-41 Chair is Stephen R Whitesell of VTech (swhitesell@vtech.ca)  SHHH study Research Audiologist is Linda Kozma- Spytek of Gallaudet University’s Technology Access Program (linda.kozma-spytek@gallaudet.edu)