Thread Subject: Re: Subpart A- Draft - TTY definition
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From: Gregg Vanderheiden
Date: Wed, Mar 14 2007 7:10 PM
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TTY. An abbreviation for teletypewriter. Machinery or equipment that employs
interactive text based communications through the transmission of coded
signals 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.
Rationale: Clarifies that the term TTY includes mixed voice and text
communications so that technical standards that use the term TTY also apply
to intermixed communications, not just text-to-text. Per Jim T - TTY should
be defined in Subpart A as complying with EIA/TIA 825, the Baudot standard.
1. TTY used to be teletypewriter (which is what the first TTYs were)
but has migrated to mean other devices today. Should change to "Originally
2. Good VCO HCO edit.
3. Agree with Jim that the EIA/TIA 825 should be in the standard.
TTYs in the US use 825 and other codes (Turbocode for example) so we can't
use that in the definition. (good catch Jim).
4. it says they MAY include TDDs etc. they DO include
those - but that terminology is not used anymore. ALSO - very confusing to
use those terms (and text telephone) now since they may also be used for
non-TTY text communication devices and phones. Since we don't use those
terms in the standard - and they are now getting ambiguous (particularly
text telephones and computers with modems) and anyone who knows TDD already
knows TTY (so there is no need to use TDD to get to TTY) I would suggest we
simplify this by sticking to TTY and what it means in this document.
5. Should point out that the code is sent as audio not data across the
that would give us.
TTY. Originally an abbreviation for teletypewriter. Machinery or equipment
that allows interactive text based communications through the transmission
of coded signals sent as 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.
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