Newsgroups: bit.listserv.deaf-l
Date:         Tue, 18 Aug 1992 16:11:33 BST
From:         Bosco Keown <KEOWN@WINVMC.VNET.IBM.COM>
Subject:      TDDs, modems, telecoms, etc....
X-To:         DEAF-L%SIUCVMB.BITNET@pucc.Princeton.EDU

Ref:  Postings by Dave Windley and Bryce Carey a while ago

Warning: long posting.

Bryce and Dave -- I read your postings with mixed feelings. Although
you made some perfectly valid points, I disagree with a lot of them
mainly because of the environment in which I work and the first--hand
access which I have to what is happening in the telecommunications
business. I'll try to explain. This is rather long and late -- I apologize
for that, but I haven't been anywhere near DEAF-L for ages.

>I believe the point of having 2400 bits/sec speed capability is so
>that people with standard ASCII computer modems can actually call and
>be called by people with TT (Text Telephones, which supercedes the 'TDD'
>designation.)

Wrong. This simply *wouldn't* work. Period.

>The issue is definitely NOT how fast one can type, or read. The issue
>is how much access one has to the vast array of communications devices
>existing in the world.

Rubbish. At least 90 percent of people who use Textphones have TDDs with
one line displays and 300 baud max. These can't cope with 2400 baud input
streams. You have to consider that the average reading speed of most deaf ppl
in INTERACTIVE phone conversations is much lower than normal. There *is* an
ergonomical consideration in using 300 baud.

>The problems you mention with display speed and reading speed are easily
>dealt with by proper computer buffering of data recieved. The problem
>with MOST existing TDD is that they are poorly designed. They are limited
>by assumptions such as you have made that the only speeds necessary are the
>speeds required by a human typist or reader.

>Most all TDD built today are built with microprocessor chips. Many of them
>have memory buffers with scroll-back capability. It is incredibly cheap
>and easy to include more memory and a smidgen more software in these things
>to deal with the requirements of a one line display. For that matter, it
>is also incredibly cheap nowadays to include a multi-line LCD display in
> TDD.

Well this may be true, but the truth is....
most deaf people don't need all the bells and whistles....anyway, we are
talking about INTERACTIVE conversation, with one person able to interrupt
the other person. Baudot allows this...300 ASCII/CCITT does to some
extent, but you often get dropped lines. At higher speeds, the handshake
is going to be too tentative for this.And 4-line LCD displays are
excruciatingly hard to read unless you're at the right angle and
your eyes can cope with ridiculously poor contrast.

>Most BBS systems use a start/stop data protocol to control how many
>characters are transmitted at a time. Usually a BBS system is set up to
>transmit a full screen of text at a time, but this is optional. There is
>nothing to prevent a well designed TDD from scrolling one line at a time
>from a memory buffer containing a full screen of lines.

There are factors which prevent this. The main one is economics.
TDD manufacturers do not make lots of profit because the laws of supply
and demand, when applied to TDDs, don't allow for very much of a profit
margin per TDD. So there's little cash to be invested in serious
development. But lets not get bogged down into what can be done with
existing technology. It's all defunct anyway. I'll explain later.

>Dave Windley's comment was that the COMPUTER modems built that work with
>old style 45.45 bps and also work with ASCII codes are mostly built
>with a top speed of 300 bps. When one pays $300-$400 for a modem nowadays
>one expects to get at least 9600 bps and FAX modem capability PLUS
>special error correction and data compression protocol converters.
>There is really NO REASON AT ALL that the hot shot ASCII modems
>could not be made to work with 45.45 bps TDD standards if there were
>a market demand from deaf people for such things.

No company is prepared to reverse--engineer their products for retro--
compatibility like this. It's just not cost--effective.

>MOST high speed modems such as 2400 bps modems and up are built with
>microprocessors in them to handle the code protocols required. These
>modems are now in the under $100 price range. Windley's comment is
>that most (?all?) TDD compatable modems STILL sell for $300 on up.
>Why the difference? Is it a conspiracy to keep the deaf poor and
>technologically backward? No, I think it is simply a lack of
>foresight and imagination on the part of those who design these
>things for the market.

The difference is (again) economics of scale: the law of supply and demand
dictates the price of modems and tdds....currently there is a far
greater demand for stand-alone and card modems of all kinds, but
the demand for tdds is relatively low...and the manufacturing process
for tdds is relatively expensive...foresight and imagination don't
count for much when you have trouble enough making a profit in the
first place.

>Bosco, you work for IBM. Why not make this suggestion to your designers?

Ay, there's the rub. But we aren't working on this. I actually
work in the Networking Systems part of IBM's business, and a lot of
the work being done here is actually on computer-based telephony, personal
and desktop videoconferencing. The trend with IBM and the Telecommunication
Companies (e.g. British Telecom) is in the development of global high-speed
networks which support data, video, and voice. I am pretty confident that
a 5 year span will see these technologies become widespread, and so TDDs
will more or less become obsolete. So there's very little to be gained from
improving existing TDD technology.

In fact, BT have just announced a far--reaching plan for a global high-speed,
high-bandwidth data/video/voice global network. Say goodbye to the humble
TDD, folks. In 5-10 years, everyone will have their own portable personal
communications thingy which will allow people to type to each other/talk
to each other/send each other data/see each other, all at the same time.
I *guarantee* it.

Bosco.

John Bosco Keown,
IBM UK Laboratories, Ltd., Hursley Park, Winchester, England.,
Internet: keown@winvmc.vnet.ibm.com
Comments: Gated by NETNEWS@AUVM.AMERICAN.EDU