Thread Subject: Re: teitac-telecom, PSTN Reference

Note

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From: Tom Brett
Date: Sun, Apr 01 2007 6:45 AM

Jim said:

"...but it meets the accessibility requirements on its own and interoperates
(looking only at accessibility) with all other systems that the procuring
agency finds necessary, it's compliant."

>From this I think it is meant that it would be alright to develop a script
or accessibility process that would permit AT to work with the telecom
system. The vendor would be permitted to add-on scripting to the
application that would make it accessible.

If there have been scripts developed, for example Jaws scripts, which would
allow a blind user to operate a GUI type telecom system even though the
bitmaps are not labeled, I don't see the application being considered
compliant. While the application would be accessible it would not meet the
standards.

Should there be another type of exception to the rule that say...if the
application can be made accessible without complying with the standards, the
application complies with the standards?

Tom Brett

-----Original Message-----
From: = EMAIL ADDRESS REMOVED =
[mailto: = EMAIL ADDRESS REMOVED = ] On Behalf Of Jim Tobias
Sent: Saturday, March 31, 2007 9:19 PM
To: 'TEITAC Telecommunications Subcommittee'
Subject: Re: [teitac-telecom] teitac-telecom, PSTN Reference

I don't get your point. Anything the feds use for voice communication, be
it internal, external, private,
public, gateway, intercom, wireless, CB, ... anything -- it's all E&IT, and
thus covered. If a vendor
uses a proprietary system from top to bottom, but it meets the accessibility
requirements on its own
and interoperates (looking only at accessibility) with all other systems
that the procuring agency
finds necessary, it's compliant. Am I missing something? As much as we may
want the telecom industry
to adhere to some non-proprietary standard, I don't think we can use 508 to
make that happen.

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


> -----Original Message-----
> From: Gregg Vanderheiden [mailto: = EMAIL ADDRESS REMOVED = ]
> Sent: Saturday, March 31, 2007 7:07 PM
> To: 'TEITAC Telecommunications Subcommittee'
> Subject: Re: [teitac-telecom] teitac-telecom, PSTN Reference
>
> Hi Tom
>
> Remember that there were three types of systems proposed.
>
> The Public Analog, the Public IP and all other closed systems.
>
> All of the government phones connect to the PSTN or emerging
> IP/SIP systems.
> If they didn't you couldn't make a call.
>
> Most of the government phones are part of a system though and
> only connect
> to the PSTN through gateways or call managers. Making a
> call from one
> phone to another inside an agency may not ever touch the
> PSTN. It would
> simply be phone to phone. Some of those phones use
> different standards and
> some use proprietary methods to communicate between phone and
> between the phone and the call manager/server/gateway to the PSTN.
>
> The problem then breaks down into three parts.
>
>
> 1) can the person with a disability use the terminal device
> (phone) and/or can they connect any AT they need to it.
>
> 2) can the connection between the terminal device (phone) and
> the public network (or between two phones not on the public
> network) carry the voice and text and possibly video reliably
> and accurately.
>
> 3) when the call hits the public phone system, is it (the
> voice, text and possibly video) in the right format to travel
> reliably on the network and to work with the devices
> (standard phones or AT) at the other end.
>
> What will work on the PSTN is different from what will work
> on the IP/SIP network. And, if the two ends done use the
> same protocol or support at least one common 'universal'
> format for voice/text/video then the call
> cannot be completed. Hence the need for established
> standards for both the
> PSTN and the IP/SIP networks.
>
>
>
> Does this help?
>
>
> Gregg
> -- ------------------------------
> Gregg C Vanderheiden Ph.D.
>
>
>
> > -----Original Message-----
> > From: = EMAIL ADDRESS REMOVED =
> > [mailto: = EMAIL ADDRESS REMOVED = ] On Behalf
> Of Tom Brett
> > Sent: Saturday, March 31, 2007 5:09 PM
> > To: 'TEITAC Telecommunications Subcommittee'
> > Subject: Re: [teitac-telecom] teitac-telecom, PSTN Reference
> >
> > How would a public phone system be defined?
> >
> > I am not sure it can be said that all government telecommunication
> > systems fall into a PSTN or IP classification. If the government is
> > using something other than a PSTN or IP system it would need to be
> > considered public.
> >
> > Tom Brett
> >
> >
> > -----Original Message-----
> > From: = EMAIL ADDRESS REMOVED =
> > [mailto: = EMAIL ADDRESS REMOVED = ] On Behalf Of Gregg
> > Vanderheiden
> > Sent: Saturday, March 31, 2007 3:52 PM
> > To: 'TEITAC Telecommunications Subcommittee'
> > Subject: Re: [teitac-telecom] teitac-telecom, PSTN Reference
> >
> > See previous post.
> >
> > We only need to talk about the public phone systems. (The
> > PSTN and IP)
> >
> > For other systems - we should treat them as proprietary and
> keep our
> > hands off until they meet with the public systems.
> > At that time they would need to be in the common public format.
> >
> > There are too many non-public technologies and it would not be
> > possible or appropriate to specify what form they should use
> > internally.
> >
> >
> >
> > I think the Two Tier approach may be appropriate though.
> >
> >
> > A general guideline (that is testable)
> > - under it the specific testable guidelines where they are
> > appropriate
> > - (sufficient techniques would not be in the guidelines but in
> > support docs from Access Board.
> >
> >
> > Gregg
> > -- ------------------------------
> > Gregg C Vanderheiden Ph.D.
> >
> >
> > > -----Original Message-----
> > > From: = EMAIL ADDRESS REMOVED =
> > [mailto:teitac-telecom-
> > > = EMAIL ADDRESS REMOVED = ] On Behalf Of Jasionowski, Tony
> > > Sent: Monday, March 26, 2007 1:17 PM
> > > To: = EMAIL ADDRESS REMOVED =
> > > Subject: [teitac-telecom] teitac-telecom, PSTN Reference
> > >
> > > Paul,
> > > Noted, PSTN is also not acceptable for the reasons you
> passionately
> > > mention, therefore, I will investigate other suitable
> alternatives.
> > > Tony Jasionowski
> > > Panasonic
> > >
> >
> ----------------------------------------------------------------------
> > >
> > > Message: 1
> > > Date: Mon, 26 Mar 2007 09:28:09 -0600
> > > From: "Michaelis, Paul R. (Paul)" < = EMAIL ADDRESS REMOVED = >
> > > Subject: Re: [teitac-telecom] teitac-telecom, PSTN Reference
> > > To: "TEITAC Telecommunications Subcommittee"
> > > < = EMAIL ADDRESS REMOVED = >
> > > Message-ID:
> > >
> > >
> >
> < = EMAIL ADDRESS REMOVED =
> > > m>
> > >
> > > Content-Type: text/plain; charset="us-ascii"
> > >
> > > Tony,
> > >
> > > Quoting from the web page you cited:
> > >
> > > "Public Switched Telephone Network communications (PSTN,
> T.70) The
> > > collection of interconnected systems operated by the
> > various telephone
> > > companies and administrations (telcos and PTTs) around the
> > world. Also
> > > known as the Plain Old Telephone System (POTS) in contrast
> > to xDSL and
> > > ISDN (not to mention other forms of PANS)."
> > >
> > > Note that this definition seems to say that services such
> > as ISDN are
> > > *not* considered to be PSTN. Presumably, this would also
> mean that
> > > digital telephones, operating behind a PBX, are not PSTN. These
> > > phones are not IP either. This would mean that the proposal to
> > > classify equipment as either PSTN or IP will leave an
> > entire category
> > > of telecom equipment without an obvious home.
> > >
> > > A reason why I am passionate about this issue is that
> I've wasted a
> > > tremendous amount of time over the past seven years, arguing with
> > > people
> > > -- including people in my own company -- about how to
> interpret the
> > > Section 508 requirements. "This requirement means this!"
> "No, it
> > > means that!!!" As part of the Section 508 refresh, we need
> > to write
> > > unambiguous requirements that cannot be misinterpreted.
> > Without that,
> > > contract officers will continue to buy whatever the heck
> they want,
> > > manufacturers will continue to sell inaccessible solutions to the
> > > government, and the likelihood that my company will let me build
> > > anything else will be close to nil.
> > >
> > > Getting back to the use of "PSTN" to describe non-IP
> > phones, my fear
> > > is that some people who are looking for an excuse to avoid
> > investing
> > > in accessibility -- including people in my own company --
> > will claim
> > > that ISDN and digital phones behind a PBX are exempt because they
> > > don't fall into either category. During the next seven
> > years, I want
> > > to spend more time building solutions, and less time
> arguing about
> > > whether they ought to be built.
> > >
> > > -- Paul Michaelis
> > >
> > >
> > >
> > >
> > > -----Original Message-----
> > > From: Jasionowski, Tony [mailto: = EMAIL ADDRESS REMOVED = ]
> > > Sent: Monday, March 26, 2007 7:42 AM
> > > To: = EMAIL ADDRESS REMOVED =
> > > Subject: [teitac-telecom] teitac-telecom, PSTN Reference
> > >
> > > Paul,
> > > "wired analog and wired non-IP digital" seems odd
> > considering we also
> > > have "cordless analog and digital". I suggest we stick with
> > PSTN for
> > > now unless someone can propose acceptable alternative term. FYI,
> > > anyone can easily find the definition of PSTN at several
> > web sites including:
> > > http://dictionary.reference.com/browse/pstn
> > > Therefore, PSTN may not be so confusing after all.
> > > Tony Jasionowski
> > > Panasonic
> > >
> > >
> > > Message: 1
> > > Date: Sat, 24 Mar 2007 17:41:44 -0600
> > > From: "Michaelis, Paul R. (Paul)" < = EMAIL ADDRESS REMOVED = >
> > > Subject: Re: [teitac-telecom] Telecommunications Working
> > Group- Draft
> > > 1 Template for 508 in WORD
> > > To: "TEITAC Telecommunications Subcommittee"
> > > < = EMAIL ADDRESS REMOVED = >
> > > Cc: = EMAIL ADDRESS REMOVED = , Creagan Tim
> > > < = EMAIL ADDRESS REMOVED = >
> > > Message-ID:
> > >
> > >
> >
> < = EMAIL ADDRESS REMOVED =
> > > m>
> > >
> > > Content-Type: text/plain; charset="us-ascii"
> > >
> > > 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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