Thread Subject: Re: Telecommunications Working Group- Draft 1Template for 508 in WORD

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From: Jim Tobias
Date: Mon, Mar 26 2007 7:05 AM

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From: Jim Tobias [mailto: = EMAIL ADDRESS REMOVED = ]
Sent: Monday, March 26, 2007 9:07 AM
To: 'Michaelis, Paul R. (Paul)'
Subject: RE: Telecommunications Working Group- Draft 1 Template for 508 in
WORD


I agree with Paul's points here on platform terms and definitions.

I want to push it further to help us clarify the structure of our report.
Looking at all of the flavors of "real-time voice
conversation" (which we should use instead of "voice communication" because
it is clearer and more constrained),
there are obviously too many varieties to put every single one in the body
of the report in the same location. I think
this provision may be a strong argument in favor of the "two tier" approach.

For example, how about this for the revised text of 1194.23(a):

"Products or systems that provide real-time voice conversation shall provide
real-time text conversation, both direct and relayed."

Then the second tier spells out the additional requirements for each
platform.



***
Jim Tobias
Inclusive Technologies
+1.732.441.0831 v/tty
+1.908.907.2387 mobile
skype jimtobias




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From: Michaelis, Paul R. (Paul) [mailto: = EMAIL ADDRESS REMOVED = ]
Sent: Saturday, March 24, 2007 7:42 PM
To: TEITAC Telecommunications Subcommittee
Cc: Creagan Tim; Brenda Battat; = EMAIL ADDRESS REMOVED = ; Jim Tobias
Subject: RE: Telecommunications Working Group- Draft 1 Template for 508 in
WORD


Regarding the reference to "PSTN" versus "IP" in many of the proposed
requirements, I agree that IP telephones should be treated differently but
am concerned that describing the non-IP systems as "PSTN" will create a lot
of confusion.



The "PSTN" is the Public Switched Telephone Network. If asked to describe a
PSTN telephony endpoint, I imagine that most telecom specialists would say
it was an analog device that complies with the FCC regulations that govern
residential telephones. If we use this definition, I can't remember the
last time I've seen a government procurement of telecom equipment that falls
into this category.



There are at least three different categories of non-IP wired telephones in
common use today:



Residential analog. (This is what most folks would classify as a "PSTN
phone.")



Enterprise analog. (The distinction between these phones and residential
analog sets is that the enterprise sets connect to the PSTN via a PBX or
switch that is owned by the enterprise. An important electrical distinction
is that, unlike enterprise analog telephones, residential telephones are
required to do "automatic loop length compensation" to account for
distance-related differences in electrical resistance and capacitance in the
line between the phone and the associated central office. Another important
distinction is that many enterprise analog solutions are actually hybrid
analog/digital sets. The audio stream is carried as traditional analog,
supplemented by digital signaling that, for example, controls the phone's
display.)



Enterprise digital. (This is what is purchased in the vast majority of
non-IP wired telephony procurements by the government. All audio
transmissions entering or leaving the phone are digitally encoded, typically
using the G.711 algorithm that I described in a previous message. Signaling
and call control is also digital, typically using protocols that are
proprietary to the individual manufacturers.)



Wired residential analog systems, wired enterprise analog systems, and wired
enterprise digital systems are able to transmit Baudot TTY signals with 100%
reliability. IP telephony is different.



Depending on network characteristics, the mechanisms that are used in order
to transport voice signals within IP networks are not always suitable for
transporting Baudot TTY tones. Common sources of impairment include packet
loss and the use of voice-optimized audio compression algorithms, such as
G.729. For this reason, a traditional TTY device used in conjunction with
an IP phone (for example, via an acoustic coupler) is not always going to be
reliable.



The good news is that, although not yet in common use, there are
international standards that describe how to transport text and Baudot tones
reliably on IP networks. In general, these techniques do not use the same
audio encoding and transmission mechanisms that are used for voice. I agree
completely that the availability of these techniques, coupled with the
inherent unreliability of Baudot TTY transmissions via the "voice channels"
of IP telephone networks, makes it essential that we treat IP telephony as a
special case in the Section 508 refresh.



Getting back to the original topic of my message. We need a term other than
PSTN to describe non-IP wired telephony. Ideally, it should be a term or
description that would make sense to someone who is not knowledgeable about
telephone engineering. To start the ball rolling, I suggest "wired analog
and wired non-IP digital" as a substitute for PSTN. (I deliberately use the
word "wired" because wireless devices have special characteristics that may
need to be addressed separately.)



-- Paul Michaelis






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From: Gregg Vanderheiden [mailto: = EMAIL ADDRESS REMOVED = ]
Sent: Friday, March 23, 2007 2:02 PM
To: 'Brooner Mary-AMB004'; = EMAIL ADDRESS REMOVED = ; = EMAIL ADDRESS REMOVED = ;
= EMAIL ADDRESS REMOVED = ; 'Takemura, Michael'; 'Karen Peltz Strauss'; 'Lori McGarry';
Michaelis, Paul R. (Paul); = EMAIL ADDRESS REMOVED = ; 'Debbie Cook'; 'Fred Lucas';
'Jasionowski, Tony'; 'Brett, Thomas F'
Cc: 'Creagan Tim'; 'Brenda Battat'; = EMAIL ADDRESS REMOVED = ; 'Jim
Tobias'
Subject: RE: Telecommunications Working Group- Draft 1 Template for 508 in
WORD



Hi Mary,



I just added my notes to the draft that you circulated from DIANE. I
made all my comments in blue so they are easy to find.



I also included a copy with the changes marked with double curly brackets
for those whose screen readers don't announce color changes.





As I mentioned, I can be on the Telecom Call this week and next due to break
and labwork.




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






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From: Brooner Mary-AMB004 [mailto: = EMAIL ADDRESS REMOVED = ]
Sent: Thursday, March 22, 2007 9:51 AM
To: = EMAIL ADDRESS REMOVED = ; = EMAIL ADDRESS REMOVED = ; = EMAIL ADDRESS REMOVED = ; Takemura,
Michael; Karen Peltz Strauss; Lori McGarry; Gregg Vanderheiden; Michaelis,
Paul R. (Paul); = EMAIL ADDRESS REMOVED = ; Debbie Cook; Fred Lucas; Gregg
Vanderheiden; Jasionowski, Tony; Brett, Thomas F
Cc: Creagan Tim; Brenda Battat; = EMAIL ADDRESS REMOVED = ; Jim Tobias
Subject: Telecommunications Working Group- Draft 1 Template for 508 in WORD

All -



The committee made a request in this week's meeting for me to circulate our
draft template in WORD as it is the medium most are familiar with. So, this
is Draft 1 which was mostly prepared by Diane Golden. Thank you, DIANE.



Gregg VanderHeiden has a draft with lots of edits. It is on the Wiki for our
subcommittee. I would ask Gregg, if possible to circulate his contribution
in WORD to this group also.



This allows folks to study the document and to edit it. I would ask, if you
want to make editting contributions that you copy the template, make your
edits and identify in the Subject line that it is an edit.



Thanks, Mary Brooner

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