[misc.handicap] TDD modem add-on to ASCII system Query

mbeck@ai.mit.edu (Mark Becker) (06/13/91)

Index Number: 16032

Greetings -

I have, in front of me, a design for a TDD <--> ASCII modem.  I built
one for an old CP/M system for use in a computer bulletin board system
and it works.

The current design parallels it with a Hayes SM-1200 and the BBS
handles TDD/300/1200.  It could go faster than that; the hardware on
will handle up to something like 19,200.

I'm considering the idea of putting the modem into a standalone
package (user gets or builds the modem, attaches an external ASCII
modem to suit existing needs, plugs a common cable into his computer,
and is on the air) but have no idea as to how many people might be
interested in such a thing.

Nor have I any idea of the feature set that ought to be included with
such a beast.  The basic unit, along with the software driver written
to "prove the point", acts like the attached external modem.. with the
difference of an extra wire or two to handle some signalling stuff
(like CTS/RTS).

Your suggestions are invited.  It might be useful to include the
misc.handicap mailing list in such a discussion.. but if not, use
e-mail to forward your ideas and comments.

Regards,
Mark Becker
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John.Zima@p0.f225.n260.z1.fidonet.org (John Zima) (06/28/91)

Index Number: 16491

Mark, I'd be interested in learning more about your TDD/Modem as I have
an immediate need for one on my bbs.  Will it conform to the Hayes
command standard?  How do you handle the switch over to Baudot from
ascii?  etc.  You can send me netmail to 1:260/225.  Will you have a kit
available or schematics to build from?  Thanks   JFZ.

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