Thread Subject: Re: TTY definition

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From: Rex Lint
Date: Thu, Jun 21 2007 2:40 PM

I was obiously working on this definition in the wrong forum (Subpart A) -
I'd proposed changes on the wiki:

http://teitac.org/wiki/Definition_-_TTY_-_May_30_Draft

to wit,



An abbreviation for teletypewriter. Machinery or equipment that enables
interactive text based communications through the transmission of
frequency-shift-keying audio tones across the telephone network. As used in
this part, the term TTY includes text-to-text communications along with
voice and text intermixed communications such as voice carry over and
hearing carry over. TTYs may include, for example, devices known as TDDs
(telecommunication display devices or telecommunication devices for deaf
persons) or computers with special modems. TTYs are also called text
telephones.

Discussion or Rationale

1. It's TTY that first made text-based communication possible, it didn't
"employ" text-based communication.

2. A mention of FSK "audio tones" is added because a major source of
incompatibility with cellular technology has been that continuous audio
tones are used to transmit the information, consuming any idle channel time
that might otherwise be allocated to other users.





Rex Lint, Consultant
Chair, Section 508 Working Group
Information Technology Ass'n of America
PH: 603-860-7651



_____

From: = EMAIL ADDRESS REMOVED =
[mailto: = EMAIL ADDRESS REMOVED = ] On Behalf Of Gregg
Vanderheiden
Sent: Wednesday, June 20, 2007 6:39 PM
To: 'TEITAC Telecommunications Subcommittee'
Subject: Re: [teitac-telecom] TTY definition



The term 'product' doesn't eliminate gateways (which aren't TTYs). Gateways
can allow users to send and receive etc. Maybe create and view?

A TTY modem on a computer would be a terminal. But if it was just a modem
- it wouldn't be able to meet our guidelines and wouldn't be a TTY .

So I think we need to stick with terminal.



RE PSTN - we somehow have to get in here that the terminal can be connected
to the PSTN. Otherwise support for TIA-825 would not make it a TTY.



So that gives us



TTY

An abbreviation for teletypewriter. A terminal that connects to the PSTN
directly or through a phone and that allows users to send and receive
real-time text communications in compliance with TIA-825-A, A Frequency
Shift Keyed Modem For Use On The Public Switched Telephone Network




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






_____


From: = EMAIL ADDRESS REMOVED =
[mailto: = EMAIL ADDRESS REMOVED = ] On Behalf Of Jim Tobias
Sent: Monday, June 18, 2007 5:43 PM
To: 'TEITAC Telecommunications Subcommittee'
Subject: Re: [teitac-telecom] TTY definition

why does it have to be a dedicated tty terminal? what about a tty modem
implemented on a desktop pc? and why duplicate pstn -- 825 only works on the
pstn. how about:



TTY

An abbreviation for teletypewriter. A product that allows users to send and
receive real-time text communications in compliance with TIA-825-A, A
Frequency Shift Keyed Modem For Use On The Public Switched Telephone
Network.



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






_____


From: Gregg Vanderheiden [mailto: = EMAIL ADDRESS REMOVED = ]
Sent: Monday, June 18, 2007 6:06 PM
To: 'TEITAC Telecommunications Subcommittee'
Subject: Re: [teitac-telecom] TTY definition

Hmmm



Just noticed that our definition would cover a gateway, a router and other
equipment/products in the pipeline and it shouldn't. It wouldn't be any
product but just user terminals. But we don't want to capture IP terminals
in the process. Also shouldn't be send-only or receive-only terminals (they
exist) because we use the term to get people out of connecting send/receive
terminals. So I think maybe something like



TTY

An abbreviation for teletypewriter. A terminal that allows users to send
and receive real-time text communications on the PSTN in compliance with
TIA-825-A, A Frequency Shift Keyed Modem For Use On The Public Switched
Telephone Network.




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






_____


From: = EMAIL ADDRESS REMOVED =
[mailto: = EMAIL ADDRESS REMOVED = ] On Behalf Of Jim Tobias
Sent: Monday, June 18, 2007 12:50 PM
To: 'TEITAC Telecommunications Subcommittee'
Subject: Re: [teitac-telecom] TTY definition

I think it can be shorter. For example, TIA-825 already mentions PSTN. How
about:



TTY

An abbreviation for teletypewriter. Any product used for real-time text
communications in compliance with TIA-825-A, A Frequency Shift Keyed Modem
For Use On The Public Switched Telephone Network.



I changed "device" to "product" to allow for software TTYs.

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






_____


From: Gregg Vanderheiden [mailto: = EMAIL ADDRESS REMOVED = ]
Sent: Monday, June 18, 2007 3:16 PM
To: 'TEITAC Telecommunications Subcommittee'
Subject: [teitac-telecom] TTY definition

How about this.





Definition

TTY

An abbreviation for teletypewriter. Device for real-time text based
communications through the transmission of coded signals across the public
switched telephone network (PSTN) in compliance with TIA-825-A, A Frequency
Shift Keyed Modem For Use On The Public Switched Telephone Network.





I thought of a lot of additional sentences to elaborate on this but
definitions should be short and keep to just those things that define the
word. This seemed to be the essence of what the TTY was. At least for the
purposes of our standard. (other countries might use the term differently,
and some, but not all, TTYs support other formats - but this is what makes
something a TTY - and is what we mean in our standard.)








Gregg

------------------------

Gregg C Vanderheiden Ph.D.
Professor - Depts of Ind. Engr. & BioMed Engr.
Director - Trace R & D Center
University of Wisconsin-Madison
< <http://trace.wisc.edu/> http://trace.wisc.edu/> FAX 608/262-8848

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