Thread Subject: Re: Volume Gain (2.2-E)

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From: Brooner Mary-AMB004
Date: Tue, Sep 11 2007 12:10 PM

The reason no "real" 20 dB built in product has made it to the 508 marketplace is because it would violate FCC rules... Here's a note from one of TIA's experts on this issue... Steve Whitesell

Dropping from 20 to 18 dB makes no sense and would NOT meet the FCC requirements. Part 68.317 is 12 dB min, 18 dB max. The 20 dB requirement in 508 is a minimum. So having 508 changed to "at least 18 dB" is incompatible with 18 dB being a max in Part 68.

Mary Brooner/TIA
-----Original Message-----
From: = EMAIL ADDRESS REMOVED = [mailto: = EMAIL ADDRESS REMOVED = ] On Behalf Of Diane Golden
Sent: Tuesday, September 11, 2007 2:11 PM
To: 'TEITAC Committee'
Subject: Re: [teitac-committee] Volume Gain (2.2-E)

Correct me if I am wrong, but as I read 68.317 the FCC minimum requirement for gain is only 12 dB without significant peak clipping. The 18 dB is a gain maximum that can only be exceeded if the phone is equipped with the automatic reset to default. So I'm not sure how many phones are actually built to much beyond the 12 dB level . . .

Diane

-----Original Message-----
From: Gregg Vanderheiden [mailto: = EMAIL ADDRESS REMOVED = ]
Sent: Tuesday, September 11, 2007 12:18 PM
To: = EMAIL ADDRESS REMOVED = ; 'TEITAC Committee'
Subject: RE: [teitac-committee] Volume Gain (2.2-E)


Thanks Diane,


Couple things.

1) Also include the "products typically held up to the ear" part. This
eliminates computers and other things including speaker phones.

2) We removed telecom from this language. Term is ambiguous now.

3) You said FCC as 12-18 in one place then 12 in another.
Did you meant to change 20 db limit down to 18?

Changing it from 20 db down to 18 db to match FCC would reduce perceived loudness by only 15%.

If phones today do 18db but not 20 db. Can we move down to this?


(dropping from 20 db down to 12 db is a loss of volume of almost half (it would be 43% lower perceived volume.)


20 db = 4x
12 db = 2.3x (43% less than 20 db)
18 db = 3.48x (13% less than 20 db)


CONCLUSION:
We could drop from 20 db to 18 db to meet FCC but 12 db would be a significant drop- close to half.



Gregg
-- ------------------------------
Gregg C Vanderheiden Ph.D.



> -----Original Message-----
> From: = EMAIL ADDRESS REMOVED =
> [mailto: = EMAIL ADDRESS REMOVED = ] On Behalf Of Diane
> Golden
> Sent: Tuesday, September 11, 2007 11:59 AM
> To: TEITAC-Committee (E-mail)
> Subject: [teitac-committee] Volume Gain (2.2-E)
>
> Sorry for the length of this message, but I've attempted to summarize
> what I think are the issues/problems with the volume gain standard
> (currently 2.2-E part 3 in the Sept 3 version). The current wording
> reads: "All other telecommunications products or systems that provide
> a function allowing voice communication must provide a gain adjustable
> from the normal unamplified level to at least 20 dB above the normal
> unamplified level as measured in accordance with the provisions of the
> FCC regulation §68.317 for volume control. The volume at the normal
> unamplified level setting must also meet the requirement in FCC
> regulation 68.317."
> 1) It appears that the intent of this volume gain standard (and the
> current
> one) was to require 20dB of built-in gain in every phone purchased.
> If it had meant compatibility with add-on AT (in-line amplifiers) or
> the ability to swap out hand sets with the required gain it should
> have read something like "Products shall have modular connectors to
> allow for the insertion of and/or compatibility with assistive
> technologies that provide at least 20 dB of volume gain without
> conflict with the FCC required built-in gain of 12 dB."
>
> 2) It appears that government agencies are unable to purchase phones
> with 20 dB of built-in volume gain as a feature of a "standard phone"
> because such phone are not manufactured. When I posed the question
> about any purchases that did conform, the Access Board responded that
> they met the standard by adding on in-line amplifiers to all standard
> phones purchased.
> At a state level, I'm not aware of any agency who has purchased phones
> with built-in 20 dB of gain as a standard feature. I've not heard of
> any federal agency who has. So the only options seem to be purchasing
> add-on AT for every phone or purchasing all phones with a specially
> amplified handset that delivers the 20 dB gain. Both these options
> are really adding an external amplifier on to each and every product
> and it is unclear how compatible this is with the 12 dB gain already
> built-in to every phone and how the reset to default requirement is
> met.
>
> 3) It appears that the built-in volume gain available on phones as a
> standard feature is the 12-18 set by the FCC.
> While the Section 508 standards attempted to set a higher level, it
> did not result in any products being manufactured to meet that higher
> level. As a result, agencies either bought the 12 dB level available
> and added-on AT or swapped out handsets only as needed by individuals
> -- or in a few cases (like the Access Board) an agency added-on AT to
> every phone purchased regardless of individual needs.
>
> 4) It appears two core questions need to be answered:
>
> A. Should the 508 standard continue to require 20 dB of built-in gain
> for every phone purchased? If so, then the standard should be
> re-written to clearly require that as there is obviously confusion
> about whether this is a built-in requirement for every phone versus it
> being OK to add-on as needed.
>
> B. Or should the 508 standard be revised to require 12 dB of built-in
> gain on all phones purchased (harmonize with the FCC
> requirements) and then require compatibility with add-on AT to reach
> gain levels of 20 dB or above?
>
> C. With either A or B, the standard should also address compatibility
> issues with add-on amplification (in the form of AT and/or a swapped
> out amplified handset) and the 12 dB gain that must be built-in per
> FCC requirements.
> Specifically, do the add-on's "double-up" amplification and what
> impact does that have on the distortion if delivered via a handset
> that cannot accommodate the doubled-up gain and if/how does the reset
> to default apply and work with the add-on?
>
> Diane Golden
> NASCIO
>
>

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