1. 7-Sep-07 Project NumberPN-3-4705-Rv1 Document TitleIEEE STIT’s Proposal on revising ITU-T P.79 SourceK. Allen Woo, Plantronics, Inc. Contact Name:K. Allen WooPhone:(831) 458-7351 Complete Address: 345 Encinal St. Santa Cruz, CA 95606 Fax:(831) 458-0423 Email:Allen.woo@plantronics.com DistributionTR-41.3.3 Intended Purpose of Document (Select one) For Incorporation Into TIA Publication XFor Information Other (describe) - The document to which this cover statement is attached is submitted to a Formulating Group or sub-element thereof of the Telecommunications Industry Association (TIA) in accordance with the provisions of Sections 6.4.1–6.4.6 inclusive of the TIA Engineering Manual dated March 2005, all of which provisions are hereby incorporated by reference. Abstract Based on IEEE STIT’s discussion at its Santa Cruz meeting, STIT created a PowerPoint slides for Allen Woo to present it at ETSI STQ meeting in last September. The presentation was further submitted to ITU-T SG12’s October meeting as a formal contribution. Telecommunications Industry Association TR41.3.3-07-11-005-M

2. 7-Sep-07 The use of WB LRs is causing confusion for designing, testing and manufacturing. Unresolved questions exist for WB LRs, scaling and relationship to narrow band ratings WB Loudness Ratings Confusion

3. 7-Sep-07  With a same loudness level for both WB and NB systems the user experience of the WB system is significantly quieter than NB (more than 6 dB)  If the end-to-end WB and NB loudness levels are calculated from a same response level the difference is about 10 dB The Problems

4. 7-Sep-07 e.g. of LRs from a Same Response NB (Table A.2 band# 4 to 17) WB (Table A.2 band# 1 to 20) WB (Table G.1, 2001) Send7.57.03.0 Receive1.70.5-4.5 End to End9.27.5-1.5 The LRs in the table below are calculated from the Nominal WB Send and Receive frequency response in the Annex of 810B

5. 7-Sep-07 TIA 810B Nominal Send Frequency Response

6. 7-Sep-07 TIA 810B Nominal Receive Frequency Response

7. 7-Sep-07 IEEE STIT recommends use the band# 1 to 20 loudness ratings in Table A.2 of Annex A of P.79 for wide-band applications in place of the “new” WB loudness ratings in Table G.1 of Annex G of P.79, 2001. This will likely be adopted by TIA TR 41.3.3 for the TIA 920-A digital WB standard This facilitates testing, and eliminates confusion with small compromise. IEEE STIT Recommendation

8. 7-Sep-07 Avoids poor correlation between WB LRs with perceived loudness Simplifies network loss planning considers mix of NB and WB conference connections Less confusion improves confidence, broadens use of standard Pros …

9. 7-Sep-07 The WB LR in Table G.1 has been issued for more than 5 years, it has been referenced by many It still has slight perceivable end-to-end WB vs. NB loudness difference, NB can be about 2 dB louder than WB Cons …

10. 7-Sep-07 Comparison of Send Weighting Factors

11. 7-Sep-07 Comparison of Send Weighting Factors cont’d

12. 7-Sep-07 Comparison of Receive Weighting Factors

13. 7-Sep-07 Comparison of Receive Weighting Factors cont’d