[comp.dcom.telecom] TDD Cost and Technology Issues

mcb@presto.ig.com (Michael C. Berch) (05/29/90)

Thanks to Ken Harrenstien and others who pointed out the rationale
behind call discounts for TDD users (i.e, that the limited bandwidth
of TDD calls requires that TDD users must make much longer calls
compared to voice users for the same amount of information exchanged).
This makes sense.

The obvious next question is, is there any hope in sight for changing
the TDD standard to something more, uh, *modern* than 45.5 or 48 baud
(this is Baudot code, right, not ASCII?)?  I understand that no
teletype-like exchange can realistically be expected to approach the
information content of a voice conversation, but are deaf people going
to be stuck with 45.5 baud forever?  I can't imagine that given
today's miniaturization of components and automated manufacturing
techniques, a device can't be built that will communicate at least 2
orders of magnitude faster at an order of magnitude less cost than
TDDs of the 1970s...

Is anybody working on this, from the standards side, or the technology
side?


Michael C. Berch  
mcb@presto.ig.com / uunet!presto.ig.com!mcb / ames!bionet!mcb

roy@phri.nyu.edu (Roy Smith) (05/30/90)

In <8413@accuvax.nwu.edu> mcb@presto.ig.com (Michael C. Berch) writes:

> I understand that no teletype-like exchange can realistically be expected
> to approach the information content of a voice conversation, but are deaf
> people going to be stuck with 45.5 baud forever?

	Why limit TDD to teletype-like exchange?  Since we're talking
about wholesale replacing of an existing standard with a better one,
why not go whole hog and do it right?  Even something as simple as a
tele-etch-a-sketch would be a great help at communications, and should
be able to easily fit into a 9600 bps data circuit (which we all know
can be crammed onto a regular voice line using V.32, PEP, or similar
technology).

	I could imagine something like a 12" x 12" digitizing tablet
with stylus (or a mouse) for sending simple drawings and a 512 x 512 x
1 bitmap screen for showing what is being drawn.  Such a device built
today shouldn't cost any more than a Teletype(tm) did 20 years ago,
and in fact probably a lot less, consisdering that what I've described
is basically a Mac Plus which is rumored to have a manufacturing cost
of just a few hundred dollars.  Of course, such a device would have to
be downward compatable with the old baudot machines since we can't
expect everyone to switch overnight.

	In fact, such a device would be useful for voice conversations
too (anybody who has seen John Maden do his "magic crayon"
play-by-play knows what I mean), but it would actually be easier to
multiplex the keyboard and stylus/mouse data streams (since they are
both already digital) than it would be to multiplex voice and
stylus/mouse.


Roy Smith, Public Health Research Institute
455 First Avenue, New York, NY 10016
roy@alanine.phri.nyu.edu -OR- {att,cmcl2,rutgers,hombre}!phri!roy
"Arcane?  Did you say arcane?  It wouldn't be Unix if it wasn't arcane!"

tob@cbnewsk.att.com (05/31/90)

In article <8413@accuvax.nwu.edu>, mcb@presto.ig.com (Michael C.
Berch) writes:

> to be stuck with 45.5 baud forever?  I can't imagine that given
> today's miniaturization of components and automated manufacturing
> techniques, a device can't be built that will communicate at least 2
> orders of magnitude faster at an order of magnitude less cost than
> TDDs of the 1970s...

AT&T currently markets a device called the 1300+ for the TDD folks. It
supports 45.5 baudot up to 1200 baud asscii and everything in between.


[Moderator's Note: Could you please get us some pricing and ordering
information for this?  Thanks.  PT]

tad@beaver.cs.washington.edu (Tad Cook) (06/01/90)

In article <8413@accuvax.nwu.edu>, mcb@presto.ig.com (Michael C.
Berch) writes:

> but are deaf people going
> to be stuck with 45.5 baud forever?  I can't imagine that given
> today's miniaturization of components and automated manufacturing
> techniques, a device can't be built that will communicate at least 2
> orders of magnitude faster at an order of magnitude less cost than
> TDDs of the 1970s...

Sure, it's EASY to use faster modems.  The problem is, you have to
communicate with all of the other TDDs that are out there.  For the
past few years they have tried to improve on this by adding 300 bps
ASCII modems to TDDs.  Of course, for keyboad-to-keyboard chatting,
this may be academic, as most folks don't type much faster than 45
baud (60 WPM) anyway.  ASCII has the advantage though of allowing full
duplex.

> Is anybody working on this, from the standards side, or the technology
> side?

EIA was working on it, but they gave up.  They found that Crown and
Ultratech are the only manufacturers, and they have been building
their stuff for years with no standards at all, other than nominal
frequencies (1.4 KHz Mark, 1.8 KHz Space) ... no tolerances for
the receiving or transmitting ends.

Last year I installed a 2400 bps modem in a new PC clone that a
hearing impaired friend bought.  Up until then she had been using 45
baud baudot, and ocasionally half-duplex 300 baud from her TDD to my
computer.

What a revealation for her when we communicated with split screen,
full duplex, and 2400 bps for the first time!  Instead of manually
switching from receive to transmit on the TDD, she could now see typed
text coming from me on the top of her screen, and she could type her
responses at the bottom.  Pretty soon we were both typing at full
speed simultaneously, and for the first time she experienced something
like a NORMAL conversation with a hearing person!

In article <8453@accuvax.nwu.edu>, roy@phri.nyu.edu (Roy Smith) writes:

> with stylus (or a mouse) for sending simple drawings and a 512 x 512 x
> 1 bitmap screen for showing what is being drawn.  Such a device built
> today shouldn't cost any more than a Teletype(tm) did 20 years ago,

Remember that the Teletypes of 20 years ago weren't purchased new by
the hearing impaired ... they were old surplus machines that were
retired from service and given away.


Tad Cook   Seattle, WA    Packet: KT7H @ N7HFZ.WA.USA.NA   Phone: 206/527-4089 
MCI Mail: 3288544   Telex: 6503288544 MCI UW  
USENET:...uw-beaver!sumax!amc-gw!ssc!tad   or, tad@ssc.UUCP

"Fred E.J. Linton" <FLINTON@eagle.wesleyan.edu> (06/09/90)

In article <8504@accuvax.nwu.edu>, <tob@cbnewsk.att.com> writes:

> AT&T currently markets a device called the 1300+ for the TDD folks. It
> supports 45.5 baudot up to 1200 baud asscii and everything in between.

to which the Moderator notes:

[Could you please get us some pricing and ordering information for this?]

I can point you to Anthony Curreri of AT&T, product (or marketing)
manager for the AT&T 1310, a similar device.  Both are, I suspect,
outgrowths of the AT&T 1300 "home banking terminal" I've mentioned
earlier here.

Curreri had, last time I checked, an AT&T Mail login, as (either)
<!curreri> (or perhaps <!acurreri>).  By his signature he seems to
call himself Tony.  He certainly had pricing / ordering / manuals data
for the 1310 at his disposal when I needed that somewhat over a year
ago, and _should_ be able to help with this 1300+ as well, even if
only to point you in the right direction.


Fred <FLinton@eagle.Wesleyan.EDU> <attmail!fejlinton> <4142427@mcimail.com>