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TR-41.3.5 Chair’s Report for February 2013

Working Group TR-41.3.5 met on Monday, February 11, 2013. The following people were in attendance:


Company / Representing

Bress, James

AST Technology Labs

Lawler, Tim

Cisco Systems, Inc.

Bareham, John

Consultant in Electroacoustics

Nixon, Jason

Industry Canada

Woo, Allen


Kramarikova, Marianna


Baum, Al

Uniden America Corporation

Whitesell, Stephen

Whitesell Consulting

Project Status: The following is a summary of the status of each Project assigned to TR-41.3.5.

ANSI/TIA-PN-470.110-D, Handset Acoustic Performance Requirements for Analog Telephones

Current Status: This document was approved for ballot subject to editorial cleanup at the November 2011 meeting, but that still has not happened. Contribution TR41.3.5-12-11-00-008-L from the November 2012 meeting discussed naming conventions for the TR-41.3 transmission performance standards. Based on that contribution, it might be appropriate to consider renaming ANSI/TIA-470.110-D to “Transmission Requirements for Analog Telephones with Handsets” or even “Transmission Requirements for Narrowband Analog Telephones with Handsets.”

Target Completion Date: June 2013

ANSI/TIA-PN-470.112, Transmission Requirements for Wideband Analog Telephones with Handsets

Current Status: Draft 0.2 of the wideband handset standard was provided in contribution TR41.3.5-13-02-006 and reviewed in a web conference on January 16, 2013. An R1 version provided Draft 0.3, reflecting the results of the web conference and input from contributions TR41.3.5-13-02-010-R1 and TR41.3.5-13-02-012. Additional editorial comments were incorporated into Draft 0.3a and provided as an LR2 version. This draft was reviewed during the current meeting, with the changes captured in TR-41.3.5-13-02-006-MR3 and identified as Draft 0.4.

The nominal SLR and RLR values specified in the latest draft are the same as for narrowband analog telephones, but the measurement procedure calls for testing with a 600 ohm source/load and zero loop instead of a 900 ohm source/load and a 2.7 km (9 kft) loop. This was done to better represent the terminal adapters / gateways to which wideband telephones are expected to be connected. Some testing work is warranted to verify if the specified SLR and RLR values are correct. Even with this uncertainty, the working group agreed to recommend that TR-41.3 send the draft out for ballot after editorial cleanup. It was noted that having to vote on the acceptability of the levels would be likely to drive the necessary measurements. Since it is a source/termination and loop issue, measurements can be made on traditional narrowband sets to verify the validity of the values specified.

During discussion about adding level requirements as an alternative to loudness ratings in the speakerphone document (see next section) the question was raised about whether a similar approach should be taken with the handset document. This has been discussed in the past as being desirable, but may slow down the completion of the handset document. No firm decision was reached on this issue.

Target Completion Date: June 2013

TR-41.3 Action Requested: Approve document to go out to ballot after editorial cleanup.

TR-41.3 Action Taken:

ANSI/TIA-PN-470.122, Transmission Requirements for Wideband Analog Telephones with Speakerphones

Current Status: Draft 0.1 of the wideband speakerphone standard was provided in contribution TR41.3.5-13-02-005, and a more complete Draft 0.2 was provided just prior to the meeting in an LR1 version. This draft was reviewed during the current meeting, with the changes captured in TR-41.3.5-13-02-005-MR2 and identified as Draft 0.3. Additional work, including the addition of level requirements as an alternative to loudness ratings, is needed before this document will be ready for ballot. The editor believes that can be done in time to have the document ready for ballot by the next meeting.

Target Completion Date: June 2013

ANSI/TIA-PN-470.132, Transmission Requirements for Wideband Analog Telephones with Headsets

Current Status: No work has been done on this document as yet. The editor believed that it would be a simple matter to take the handset document once it is completed and add the repetition tests and results averaging process necessary for the headset document. However, Allen Woo indicated there was more to it than that, with some of the requirements needing modification as well. The editor will look into this and attempt to get an initial draft completed for the next meeting.

Target Completion Date: August 2013

ANSI/TIA-PN-470.340, Feature Performance Requirements for Wideband Analog Telephones Used with VoIP Services

Current Status: Contribution TR41.3.5-13-02-007 and a subsequent R1 version provided a revised bandwidth negotiation handshake protocol between the wideband-capable telephone and the terminal adapter / gateway to which it is connected. However, Microsemi Corporation, the original proponent of the handshake protocol, has changed their opinion and submitted contribution TR41.3.5-13-02-014-L proposing to delete the protocol. Under this scenario, the telephone would always operate with wideband capability but would provide narrowband performance when connected to a narrowband pipe. This did raise a question as to whether more of a “brick wall” at around 8 kHz should be required of the receive template to reduce any 8 kHz sampling artifacts that might be present when receiving a narrowband signal.

The question of whether this document will be needed if there is no handshake protocol requirement was not thoroughly explored, but should be discussed at the next meeting.

Target Completion Date: August 2013

Additional Information: TR-41.3.5 would like to provide the following additional information.

Liaison with ETSI STQ

Contribution TR41.3.5-13-02-004 is a copy of the liaison letter sent over TR-41 Chair Steve Whitesell’s signalture to ETSI STQ Chair Andreas Kamcke informing them of the wideband analog telephone project.. This was done at the suggestion of former TR-41 participant Joachim Pomy, who is also an ETSI STQ participant. Contribution TR41.3.5-13-02-015-L is a reply acknowledging receipt of our letter and asking us to keep them informed. Although not discussed in the TR-41.3.5 meeting, the TR-41.3.5 Chair would like to suggest that another liasion letter be sent informing ETSI STQ of the progress made to date and the decision to drop the handshake protocol.

TR-41.3 Action Requested: Chair Steve Whitesell moves as an individual that a liasion letter be sent to ETSI STQ updating them on the progress of the wideband standard. If the motion is approved, should this meeting report be attached to the liaison letter?

TR-41.3 Action: Motioned seconded by xxx. Result of vote.

Wideband Magnetic Coupling

Linda Kozma-Spytek of the Technology Access Program at Gallaudet University has taken note of the wideband analog telephone work and has asked if the new standard will include requirements for wideband magnetic coupling. She indicated that a research study she conducted during last summer’s HLAA convention with cochlear implant users showed wideband speech delivered acoustically to the cochlear implant microphone improved the subjects’ understanding over that of typical narrowband speech and reduced the mental effort required. She notes this is consistent with findings by other researchers in the field. She has also confirmed with Dave Preves of Starkey that hearing aid T-coils are wideband, so this finding should be valid for wideband magnetic coupling as well.

Contribution TR41.3.5-13-02-013 is a copy of the email exchange TR-41.3.5 Chair Steve Whitesell had with Linda on this topic. Steve indicated compliance with ANSI/TIA-1083-A is proposed to be a requirement for the wideband handset document. Although that standard only contains narrowband requirements, it is likely that a wideband telephone compliant with the standard will provide a wideband magnetic signal for T-coil coupling. Further discussion in the email deals with the possibility of revising ANSI/TIA-1083-A to include wideband requirements. Linda has indicated she intends to make a more complete contribution regarding her study to TR-41.3 at future date.

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