[misc.handicap] TDD Emulation

rbarth%ka3ovk.uucp@uunet.uu.net (Dick Barth) (06/25/91)

Index Number: 16386

In Issue # 2077, Jack Rozel (st101921@brownvm.bitnet) writes:

> I don't want to steal the wind from Mark Becker's posting about an
> ascii converter for microcomputers, but I am looking for something a little
> different.  I have a laptop computer with an internal modem and I'm looking
> for an IBM software program that would let me emulate a TTY unit.  The only
> such program I know about is Microflip's FullTalk program.  It costs about $
> $300  -- does anybody know of a cheaper (maybe shareware or public domain) 
> alternative.

I hate to be the bearer of bad tidings (again) but there is no such program
and there never will be.  An ASCII modem is fundamentally incompatible with
a TDD on the hardware level, and no piece of software will ever enable the
two of them to talk to each other. (This excludes from consideration those
TDDs which have an inherent ASCII capability; I'm talking here about "true"
TDDs and not those which act like computers.)

The Microflip product is not just a piece of software.  It's a TDD modem
that happens to come with a piece of software.  The modem is what makes
the two compatible at the hardware level, and the software enables your
computer to talk Baudot (which is what the TDD uses instead of ASCII).

There are a number of other TDD modems -- computer modems that will talk
both to TDDs and (at 300 baud and under) to ASCII terminals and computers.
there is under development (as I discussed in an earlier posting) a modem
that will talk to TDDs and to computers using ASCII at 300 to 2400 baud.
The HEX BBS accepts TDD calls as well as computer calls, but it uses a 
TDD modem (the CM-4 from Phone-TTY) to do it.  There's no other way.

If you were running an original IBM-PC or PCjr you could use emulation
software by John Spalding which uses the computer's cassette port to
emulate a TDD modem.  In this case, though, you're faking a modem, not
using an ASCII modem to communicate with TDDs.

If you're interested in a discussion of existing commercial TDD modems
you may want to download a copy of "compare.tty" from file area two on
the HEX. 

Regards, 
Dick.

--- 
Dick Barth, W3HWN.   The Handicapped Educational Exchange (HEX) BBS
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